Earlier this week, CBS was trumpeting the news that "60 Minutes" would finish the season as the No. 10 show on television - marking 20 consecutive seasons the show had been there.

That's an all-but-unimaginable accomplishment - one that will never be duplicated.The shows that came closest to the "60 Minutes" record of top-10 finishes were three of Lucille Ball's sitcoms ("I Love Lucy," "The Lucy Show" and "Here's Lucy"), which spent a combined 16 seasons in the top 10 - 10 of those consecutively. And among hour-long shows, there was "Gunsmoke," which spent 13 seasons in the top 10 - seven of those consecutively.

There's just one problem. According to those old meanies at Nielsen, "60 Minutes" is going to finish No. 11.

Nielsen contends that the NBC sitcom "Fired Up" is No. 4 this season. CBS contends that a show that has only aired four times - and between No. 2 "Seinfeld" and No. 1 "ER" at that - doesn't really count.

And there is some merit to CBS's argument . . . but then Nielsen has a point.

The fact is, it's pretty much irrelevant. Whether it's 19 consecutive seasons in the top 10 or 20 consecutive seasons in the top 11, "60 Minutes' " accomplishment is all but incredible.

RUMOR IS: There are reports that CBS is about to bring "Step by Step" over from ABC as a companion piece to "Family Matters" - a show CBS signed out from under ABC a couple of months ago.

There are several indications this could come to pass:

- CBS has an option on the show.

- CBS Entertainment President Les Moonves has stated his intention of building an ABC-like "T.G.I.F." lineup on Friday nights and has already penciled "Family Matters" in at 7 p.m. on that night.

- Moonves used to be the head of Warner Bros. television division, which produces both "Family Matters" and "Step by Step."

- And Moonves, who's acquiring a reputation in Hollywood's creative community for being a loose cannon who's difficult to work for and with, recently killed a pilot he'd ordered the day before it was to shoot. And that pilot was to star "Step by Step" lead Patrick Duffy (who was also credited as an executive producer on the jettisoned show).

RUMOR IS (PART 2): There are reports that "Star Trek: Deep Space Nine" won't wrap things up at the end of next season as originally planned - that, like "Next Generation" before it, "DS9" will return for a seventh year during the 1998-99 TV season.

Now, if only KSTU-Ch. 13 could either find a time slot where the show could actually air without pre-emptions from football or baseball or hockey . . . or give the show up to a station that can.

SAY IT AIN'T SO: The trade publication Variety is reporting that there are at least tentative plans to try to put together a daytime talk/variety show starring - believe it or not - Donny and Marie Osmond.

Just one word: Ick.

CNBC SHAKEUP: Most people may be happy that the O.J. Simpson trials are over, but not the folks at CNBC.

The cable network has seen its ratings fall by 40 percent from last year, led by a big drop in the numbers for "Rivera Live" and "Charles Grodin" - two shows that did just about nothing but yack about O.J. last year.

As a consequence, CNBC is going to shake up both its lineup and its management.

The NBC-owned cable network is going to dump reruns of "Late Night with Conan O'Brien," which have bombed badly, after May 16. On May 19, CNBC will fill the time slot with a repeat of MSNBC's "The News with Brian Williams."

By this fall, look for an hourlong prime-time business news show on the cable channel.