You've come to precisely the right place. According to the bible on the subject, Dr. Thomas Graham's
Remembering Revell Model Kits (the rivised, 2004 edition), your kit is worth between $50 and $60. It was originally issued in 1954; apparently the one you've got is from that first issue. The kit has been reissued several times: as PT-212 again in 1962 (worth $20-$30), as PT-207 in 1966 ($20-$30), as PT-212 again in 1972 ($25-$30), and as PT-211 in 1975 ($25-$35). It als made appearances in a couple of Revell's extremely scarce and valuable "Gift Sets," issued in the fifties. (If you find one of those big, glorious boxes, labeled "Admiral's Fleet" or "Victory at Sea", hang onto it. They're valued at $500-$600.) The PT boat appeared one more time: with an electric motor in 1961. That one's worth $25-$35.
I built that kit several times when I was a kid; I remember it as a great fun project. (Especially those crew figures. The scale is listed as either 1/98 or 1/99, but I remember that the figures sold by AHM in its old "Minitanks" series were almost exactly the right size. My PT-212 got a full crew that way.
Hope this helps a little. Good luck.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.