On Sunday night, TV viewers can see the comedy show that made CBS brass weep. It's the season's final episode of "All in the Family" and it marks the departure from the series of Sally Struthers and Rob Reiner as Gloria and Mike Stivic.

When "The Stivics Go West" - at 9 o'clock on channel 9 - you can count on about 45 million people to go to pieces because the closing mements of the show, after 20 minutes of the usual rowdy comedy, make those farewells on the last "Mary Tyler Moore Show" look like casual ta-tas.

This is partly because the characters on "All in the Family" have more dimension than those on any other situation comedy in broadcasting history.

Writers Bob Schiller and Bob Weiskopf gave the script the kind of warm credibility that suggests more than more professionalism at work. And naturally the players - Carroll O'Connor, Jean Stapleton, Rob Reiner and Sally Struthers - may be giving even more than their usual all's because the fiction parallels fact; this was, indeed, goodbye.

"All in the Family" will continue for at least one more year, Robert A. Daley, president of CBS Entertainment, had feared he was going to lose the high-rated "All in the Family" for good at the end of this season.

So when Daly was leavig the taping of the show on March 3 with programming vice president B. Donald Grant and remarked, "There were tears coming down my cheeks," Grant replied, "Well remember - this could have been the last episode. Then you'd really be crying."

Public TV can toot its own horn as deafeningly as anybody, as it demonstrates Sunday night with a two-hour commercial for noncommercial television called "The Great American Dream Machine Revisited: 25 Years of Public TV," on Channel 26 at 8 o'clock.

Very little of the old "Dream Machine" series - one of the truly innovative public TV productions - is seen in this slapdash compilation and in fact, very little of anything is seen.

There are highlights, to be sure, and these include a recent color tape of Martha Graham's ballet "Appalachian Spring" which dissolves into a 20-year-old black-and-white version in which Graham herself danced the leading role.

Unfortunately a script, by Harvey Jacobs, that tries to tie this hodgepodge together, takes not a self-effacting or sophisticated view of public TV but instead insists on fatuous promotional pomposities.

It is bad enough to be subjected to that kind of hype from commercial TV; what we hope for from public TV is a touch of discretion, a little dignity, and the chance for us to make our own deductions about the quality of what we are seeing.