New #5 type collection follower GCRL runs an excellent site of his own called Oh My O-Pee-Chee! It fills a big hole for North American baseball collectors, visually comparing and explaining Topps (American) and O-Pee-Chee (Canadian) card differences. You might not think this is a big deal, but I sure do.
Imagine that you normally collect modern cards, but find this Hall-of-Famer for a bargain price. No problem with the front, just your typical Topps card, right?
But then you turn it over and compare the back to a 1974 Topps checklist. I assure you, the number won't match what's there. (Topps #196 is Jim Fregosi and Catfish Hunter is #7.)
Fear not, hypothetical collector, Oh My O-Pee-Chee has your back! Check out its 1974 Jim Hunter entry for scans of both Catfish cards. Did all of your concerns evaporate? For even better news, 1974 OPCs are harder to come by than their Topps equivalent and could be more valuable.
There's a complementary overlap between GCRL's coverage of the Hank Aaron specials and my own #5 post for 1974. Read them all and be an informed collector! (Or at least see lots of classic cards.)