You can identify a 203 by the metal tag that identifies it as such , but these are usually missing or caked with grease or mud , so you can't see it. Np 203 has 3 sections: the front low range box , the middle where the chain is , and the rear tail housing . The 205 is pretty much one piece. The 203 also has a unique shifter that looks like a little box that I heard was made for GM by hurst.I'm just going off of what the previous owner told me. But after seeing his shotty work!!! I'm starting to thing it's a 203. Me to! I'm running out of time