Talk about coincidence: Tonight in prime time, a new NBC made-for-TV movie and a new episode of USA Network's "Silk Stalkings" flirt with the same basic concept, looking at a beautiful woman afflicted with multiple-personality disorder. As often as TV regurgitates this particular plot, you'd think every third person in the country had the same problem.
* "Melrose Place" (8 p.m.-9 p.m., Channel 45) -- Speaking of hackneyed old TV plots, have you heard the one about the guy who gets amnesia and can't identify his attacker? Well, you heard it here last -- last week, that is, when Michael (Thomas Calabro) regained his memory and started on his own plan for revenge. Also, last week's episode ended with Jake's boat blowing up, seemingly with Jake aboard -- or did he jump overboard off camera, as in the old Republic serials of yore? If you guessed the latter, yore probably right. Fox.
* "Voices From Within" (9 p.m.-11 p.m., Channel 2) -- Usually, TV characters with multiple-personality disorder are the killers, but in this new NBC made-for-TV movie, Stephanie Zimbalist plays a three-faced woman who's the victim. What her surviving sister, played by JoBeth Williams, has to discover is which of her sister's several personalities was the victim -- the only possible path to the murderer. NBC.
* "The Native Americans" (8:05 p.m.-10:05 p.m., TBS) -- Part 1 of 3. There's no denying that this documentary series could have been more gripping and dramatic. But because it offers a point of view normally shut out of the mass media, and because the stories, especially of treaty violations and spirit-breaking "socialization" schools, are so crucial to our shared history, "The Native Americans" should be seen, discussed and applauded for its efforts.
* "Silk Stalkings" (10 p.m.-11 p.m., USA) -- Here's a more usual multiple-personality TV plot: A woman with a split personality is charged with murder. Did she or didn't she? Or both?