JOAN Rivers isn’t taking any chances with her East 62nd Street penthouse. At a party she hosted this week for her TV Land show — “How’d You Get So Rich?” — Rivers had three guards, to make sure that guests weren’t tempted to swipe any of her tchotchkes. The apartment, which Rivers bought 20 years ago, is on the market for $25 million. The comic acciden tally thanked “TV Guide,” in stead of TV Land, during her speech. When a producer piped up to correct her, Rivers backtracked, “No, no, no, no. I hate TV Guide. I spit on TV Guide. Rewind the [bleep]ing tape.”