I have noticed that the firing pin in my Walmart version 62 F is different that what is shown in the manual that came with it & what I have seen in other model 64 f rifles. Why is this?

Here is what my firing pin looks like in my 62 F from Walmart. The one is taken from Numrich gun parts, that is the one I have seen in every disassembly video on Youtube. So please if anyone has a answer to the difference in the firing pins, & perhaps which one might work better let me know. Thanks.