Difference between 4x4 and 4x2 front bumper?

[runnerC2]

I need a front bumper for my 91 4x4 4runner. I know a guy that has a bumper for a 2nd gen body style two wheel drive something. He bought it for his 4x4 truck but he didn't use it because it didn't fit. He modified it so that it bolts up correctly, but still doesn't fit right. Does anyone know how much of a difference there is? They look the same to me. For the price of free, I might just have to make it work...