distinguishing characteristics of long beds vs. short beds

Hi

First post here. Ive been looking for a 1st gen or early 2nd gen long bed Ranger for awhile now and I feel Ive overlooked quite a few because the owners don't know which beds they have. Too make matters more complicated for me the owners typically take pictures of their trucks from weird angles making it hard for me to identify which is which. are there any other identifying characteristics that I can look for? I heard that the fuel doors are different is there any merit to that?

Thanks
Matt