The 35' version that looks like a 4905 is a 4107. The 4905 is 40'. All parts are as easy to come by on either model. Some 4905's had a tag axle as well. 4 speed or auto on the 4905.
Thanks for the info, Bill! I'm jammed up all weekend but as soon as I find some time I'll do some research on the differences in models. I definitely want a 40'er, and don't want a tag. I will need the extra bay space. It wont be loaded down with all the typical RV stuff, either.