Can i buy a unchanging iphone 2g upon eBay as well as send a Sim label from my att prepaid phone to a iphone 2g which i paid for off eBay?

I have the reticent phone upon att that’s prepaid…Do we guys consider if i buy an att iPhone 3G upon eBay as well as put my prepaid Sim label in to the iPhone 3g which the iPhone 3G

Im starting to buy an att Iphone 2G upon eBay as well as wondering if i can put my prepaid Sim label from my aged att prepiad phone…and have it work upon a iPhone 2g?? . .or does a phone have