The Department of Education, faced with a doubtful future under the incoming Reagan administration, has decided to go ahead and take a big step. It has released the final regulations governing the use of its official seal.

"You're not real without a seal," sounds like an old bureaucratic maxim, but the fact as I just made it up. In the act that set up the Education Department, Congress required it to get an official seal, according to a notice in the Dec. 31 register (page 86490).

So the Institute for Heraldry was hired to put together something distinctive that would appear on letterheads, business cards, ID cards, official agency signs, and in the embossed version on legal documents, awards and such.

Department officials recently found that, though Education Secretary Shirley M. Hufstedler once spoke highly of the official seal in a speech, she never officially adopted or approved it. Thus, the need for an official register notice.

The official description in the register seems to give some weight to the thought that the seal designers looked on the new Education Department much as the Reagan people do -- as the ever-growing source of green money, nourished by the gold of a benevolent government.

The official description of the seal is: "Standing upon a mound, an oak tree with black trunk and limbs and green foliage in front of a gold rising sun, issuing gold rays on a light blue disc, enclosed by dark blue border with gold edges bearing the inscription 'DEPARTMENT OF EDUCATION' . . . . "