Shameless product placements are nothing new in Hollywood films. Think Tom Cruise drinking a Red Stripe in The Firm; think Kevin Costner gulping a cold RC Cola in A Perfect World. But this season's most blatant product placements are movies hawking other movies from the same studio. Consider these:
*SIX DEGREES OF SEPARATION (MGM) Picture in picture: A shot of the marquee at Manhattan's Waverly Twin theater, offering a double feature of 1993 MGM releases Benny & Joon and Fatal Instinct. Reasoning: ''It was an MGM movie,'' says Six Degrees director Fred Schepisi. ''I felt we might as well use MGM movies on the marquee.''
*WE'RE BACK: A DINOSAUR'S STORY (Universal by way of Steven Spielberg's Amblin Entertainment) Picture in picture: As cuddly dinosaurs rock & roll in Times Square, they bop past a theater showing -- what else? -- Jurassic Park. Reasoning: ''It's in there as a little joke, as a comedy homage to ourselves,'' says Mavy, Amblin's marketing consultant. ''There's certainly no need to promote Jurassic Park anymore.''
*BEETHOVEN'S 2ND (Universal) Picture in picture: Teenage daughter Ryce Newton (Nicholle Tom) has plastered the wall above her bed with Tom Cruise paraphernalia, including a poster for 1992's Far and Away, one of Cruise's only clinkers. Reasoning: ''She's of that age,'' says Beethoven story editor Marcus Miller, referring to her romantic interest in the pin-up boy. Plus, ''Far and Away is a Universal film.''
*WRESTLING ERNEST HEMINGWAY (Warner Bros.) Picture in picture: When Richard Harris and Piper Laurie exit a revival house in a small Florida town, they walk past a poster for Warner Bros.' 1992 weeper Forever Young. Reasoning: Says a studio spokesman, ''If it's appropriate, they'll do a little in-moment.''