Stamps used on government mail, called "Official Mail" stamps, are now officially called "Penalty Mail" stamps. But the ones coming out Wednesday still say "Official Mail USA" in big red letters at the top, though a bottom line now stipulates "Penalty for private use $300."

The new issues are a denominated 2-cent coil stamp and a 14-cent sheet stamp for post cards, replacing look-alike stopgap nondenominated stamps that were thrown into the breach earlier in the year when higher rates went into effect. They now have an identity and are in their proper attire, with black numbers that say "14" and "22."

The nomenclature is just the beginning of the confusion, convolution and complication that are awaiting collectors down the line that could make lesser souls decide to skip the issue. Fortunately, most collectors are driven by completeness and would persevere against even greater odds to avoid blanks in their collections.

For instance, for the first time since the Bureau of Engraving and Printing has been producing stamps, there are no plate numbers, not on the selvage of the 14-cent sheets and not on every 52nd stamp of the 22-cent coils of 500 and 3,000. There were no plate numbers on the 1943-1944 Overrun Countries commemoratives, but these were done by the American Bank Note Co. and an inscription on the selvage named the country represented by the flag on the stamp. The only marginal inscription on the sheets of the new stamps is the copyright.

The omission of the plate blocks was done at the direction of the Postal Service. The reason was reported to be to cut paper waste and the time spent by clerks supplying blocks. But the USPS is making copyright blocks of four and corner blocks of four available to collectors. How clerks can do this without taking time is unclear.

The stamps are being sold over the counter only at the Philatelic Center in the lobby of the Postal Service headquarters building, 475 L'Enfant Plaza West in Southwest Washington. No usual minimum requirements for blocks of four will apply in this instance, the USPS indicated.

Mail orders should be sent to Penalty Mail Stamps, Philatelic Sales Division, Washington, D.C. 20265-9997. Because of the special nature of the stamps, the division will accept orders for single stamps and combinations and waive its customary restrictions on copyright blocks or corner blocks. There is a 50-cent handling charge for each mail order.

For collectors of first-day-of-issue cancellations, life is not simple either; all they have to do is turn themselves into a federal agency. It is the only way. The stamps are forbidden for private use and couldn't be affixed on covers anyway because they are not available at post offices.

The envelopes or post cards sent in for processing by the USPS must have a federal return address. So collectors should place "U.S. Postal Service/ Washington, D.C. 20066/ Official Business" in three lines in the upper left corner.

The official return address must be done in a very specific way. It may be preprinted, typewritten or rubber-stamped on an envelope, card or gummed address label. Under no circumstances may it be written in longhand.

The address to where the first-day item is going should be in the lower right as usual, written any way as long as it is legible.

Orders must specify which stamps are wanted. Copyright blocks will be affixed on request. The cost is 22 cents for each letter-rate stamp and 14 cents for a card stamp. A 14-cent stamp desired for anything but a card requires an additional 8 cents postage. Orders must be postmarked no later than June 14. Personal checks are accepted, cash is unwelcome and payment by stamps is rejected.

The Postal Service introduced official stamps and stationery early in 1983 as a substitute for the traditional envelope with government indicium to test whether exact postal accounting agencies' mailings was possible. Official stamps were used more than a century ago, and collectors tried hard to resist observations about "the more things change . . . " The test proved effective and was applied throughout the federal establishment.

A final note for those eager to know what's in a name: Under the law, official mail is mail entitled to be delivered without prepayment. It includes the penalty mail used by the entire government except the Congress and the franked mail used by U.S. senators and representatives. Calling official mail penalty mail is intended to make it clear that it is apart from congressional mail.

The ongoing Transportation Series of coil stamps, portraying early modes of transportation, has just come up with its 19th issue, a Tricycle of the 1880s.

The latest coil is a 6-cent denomination that meets the new basic minimum per-piece rate for third-class bulk mailings by nonprofit organizations that went into effect Feb. 17.

Those acquiring stamps at post offices and affixing them on envelopes, which must bear addresses, should send the covers to Customer-Affixed Envelopes, Postmaster, Childs, Md. 21916-9991. They must add 16 cents in additional postage to meet the first-class rate.

Those preferring full processing by the Postal Service should send their envelopes, which must be addressed, to Tricycle Stamp, Postmaster, Childs, Md. 21916-9992. Three 6-cent Tricycle coils and a 4-cent Stagecoach coil will be affixed for first-class postage. The cost is 22 cents per cover. Personal checks are accepted, cash is not welcome, payment by postage stamps is rejected.

The stamp has been produced in brown by intaglio, with all text matters on top. It has been issued in coils of 500 and 3,000, with one plate number appearing on every 52nd stamp.