AN EXCEPTIONAL collection of American weathercocks at the Newcomer/Westreich gallery of American decorative arts (406 Seventh St. NW) will register with collectors throughout the country, beyond doubt, and may safely be viewed by ordinary folk. Unlike many shows of American crafts, at which one wishes some object or other were five bucks cheaper, this one offers no temptation at all to the fellow of ordinary income.

"Give you 50 bucks for that wooden horse," I said to a gallery owner, nodding towards a splendid little provincially carved steed about a foot long from Wells, Vt. (no date is hazarded for this work).

"Oh, dear," said Thea Westreich, "I'm afraid we're really too far apart. It sells for $6,000."

Well, there you are. Most of the weathercocks sell for between $5,000 and $10,000, and I mention this only so you don't go poking down there hoping to find something nice for Uncle Ed's barn.

The gallery is rightly proud to be displaying 35 weather vanes, an exceptional assemblage in this day when their rarity is notable and their prices astronomical.

The show will run through April 17; gallery hours are 10 a.m. to 6 p.m., Tuesdays through Saturdays.

American weathercocks of the 17th and 18th centuries are excessively rare, and even those of the late 19th century have for some years been collectors' items and have fetched handsome prices. A vane that may have sold for $5 in 1880 may now bring $5,000. What a pity one's grandfather did not spend his days making weather vanes and storing them in the barn.

Vanes were commonly ordered by mail from companies like Cushing and Fiske (a very handsome Cushing rooster is a mere $6,000 and a Fiske surrey with horse is also only a few thousand smackeroos).

For only a couple thousand dollars or soSee WEATHERCOCKS, Page 2, Col. 1 Cavalryman setting off into the gale; photo from Newcomer/Westreich. Galloping weather vanes at Newcomer/Westreich gallery. Photograph by Harry Naltchayan--The Washington Post. Weather Worn -- WEATHERCOCKS, From Page 1 you can buy a Howard Johnson weather vane showing Simple Simon, I believe, purchasing a pie from the pie man. These are quite rare, though not very old, and someone with affectionate memories of his first strawberry sundae, and with more money than sense, will probably wish to acquire it.

A great favorite of mine, and, alas, of the gallery as well, is a cavalryman waving a saber and setting off into the gale on a particularly nice full-bodied copper horse. It comes from rural New York, was made about 1880 and sells for $24,000. It would make a grand lamp base for a tack room.

Westreich, like most buffs of vanes, is especially ecstatic about the homemade weathercocks, some of which have the disarming openness that has long beguiled admirers of American folk art.

There is a carved "Hand of God" vane, made from a short board, now quite the worse for weather and wear. There are several vanes sawn out of metal, in hopeful imitation, no doubt, of some fancy store-bought vane at a neighboring farm.

"No need to throw away five dollars," you can hear the thrifty yeoman say. "What fool would pay five dollars? We can make one in a day that's just as good or better." Some vanes made in this brave hope are on display and are far more wonderful to the modern observer than the original maker ever dreamed.

It might be said that even in Washington it is impossible to have a satisfactory life without a weathercock to observe several times during the day and night. You never know where the next wind comes from. To speak personally for a second, I am much in debt to Gabriel, our copper eagle who sails about faithfully on his 6-foot spindle with his wings spread 31 inches. He is a modern copy, and the least puff of breeze sets him going.

The prices of these gallery vanes did not alarm me in the least. It is not necessary to buy everything you look at and enjoy, after all, and I was grateful the prices were not near enough to my own wallet that I was tempted.

People for some reason always imagine they will wander out to Fairfax or some other village over the horizon and pick up a sensational weather vane for $10. Well, happy hunting.

"We are a small gallery, but even we have 30 pickers in remote locations," Westreich said. "People have no idea how thoroughly even remote countrysides have been picked over by collectors."

Westreich believes the hideous rumors that thieves in helicopters have stolen some fine old weathercocks from off barn roofs.

She indicated the gallery weathercocks came from no such awful sources, and moreover is quite content and quite sure about the provenance of the vanes. In making substantial purchases, needless to say, it is always well to deal with a company that guarantees to stand by its assertions of authenticity, especially since there is a flourishing business in weather vane reproductions, many of which are sold to antique dealers. Which Westreich thinks is pretty awful.

No law says a modern copy has to be identified by its maker as such. There are, fortunately for collectors, experts in this field of weathercocks who can often spot a fake bullet hole or an instant patina at 10 paces.

One can only hope that some of those who view the show will be struck by the wonderful cow or rooster or whatnot, and will say it is absurd to spend $5,000 when for two bucks' worth of materials any handyman can make a vane as good or better. And probably as valuable 100 years fromnow.

With any luck at all, the skyline of Washington may blossom with a whole new generation of eagles, sheep, cows, horses, hounds and much else, all heading into the wind more or less faithfully, depending on how well they are installed and how skillful the housing is around the spindle. Perhaps there should be a city regulation that every dumb glass box of an office building had to have at least one weathercock per thousand square feet of roof surface. If this were done, we might once again get in the habit of looking at buildings.