Oh to have been in the screening room full of CBS executives who gave the go-ahead to "Private Benjamin," a definitively lowly and dozey new CBS sitcom that begins a trial run at 8 tonight on Channel 9. Did any of the Black Rock Boys actually laugh at this thing? Or did they just trust their research and audience testing to assume it was really funny at some simian level they knew to be beneath them?

All three networks are ripping off the hit Goldie Hawn comedy about a Jewish American princess who mistakenly enlists in the Army, but CBS is first on the air and is the only network authorized to use the title. Young Judy Benjamin is no longer identified as Jewish, however, and there is no reference to her schlump husband having turned up his toes on their wedding night. What's left is barrel-bottom, oopsy-daisy comedy less sophisticated than forays into the military by Martin and Lewis in the '50s and Abbott and Costello in the '40s.

In fact, "Francis Joins the Navy," starring that well-known talking mule, was funnier and more pertinent than this numb, precious, tedious wretch.

Lorna Patterson, inheriting the Hawn role, was apparently chosen for her lack of character or for the fact that she looks vaguely like Hawn when she sticks out her tongue and rolls her eyes. Eileen Brennan, so recklessly overpraised for her portrayal of Capt. Lewis in the film, repeats the part here, hemming and hawing and stretching out her reactions so as to hog screen time for herself. She's defiantly unamusing all the time .

Hal Williams, who played the drill instructor in the film, also carries over to the television show, though what good it will do him is debatable. Don Reo, who "developed" the thing for television and wrote the premiere, can congratulate himself on a laughless half-hour with not even a peep of redeeming interest. Don Sweeney's sleepytime direction is just what the script deserved. No -- just what the script deserved is never to have made it farther than Mr. Reo's out-basket.