I'm thinking its more likely that at some point your motor was changed and maybe thats all they had to use, or the parts store gave them the 79-95 302 special. What would be interesting is to see what the dizzy gear looks like. You could easily pull it out and inspect it. This would help tell you or worry you, depending on what you see. If the firing order is the 351 order, then the gear should be billet steel and smooth looking. If the order is the older flat tappet one, them the gear should look cast and rough. If not, then you should be worried. Most likely you have an older engine swap with a flat tappet cam, and you should make sure the right gear was used because alot of people dont know that.