Interesting. Lots of aftermarket parts out there, usually Chinese. I would not use the screws if they don't match, though the pump itself should work just fine as long as the gaskets seal. it's a very simple design.
Be VERY careful ordering things with just a parts number. Again, Chinese. The accuracy of the product descriptions leave a lot to be desired.
I just ordered a part for a 1999 10 HP Tecumseh generator off of Amazon I don't know what the hell they sent me, but it in no way, shape or form was ever on any sort of generator and does not match the picture/description. Oh well, free returns.