The Vegas unit is identical to the Axis unit aside from the color selection and some external styling (headlights on the Axis are horizontal but are vertical on the Vegas). They are both built at the very same plant. Note that the same inspection list above would also apply to the Vegas unit as well.
The two charges for $1200 sound like they are trying the cheat you out of $2400. Tennessee isn't very far from the plant in IN..close enough that it wouldn't be more than a tankful of gas to drive it.
As far as the roof maintenance: That sounds like a lot of work! LOL We had our 5th wheel for 10 years and I think I cleaned the roof twice (granted it probably could have used it more). It is a good idea to clean it and put a UV protectant on it but you don't have to get up there every year and seal it (really only if you have leaks and/or you notice the sealant up there is going bad). The best maintenance is just a yearly (or twice yearly) inspection: climb up and look around. If stuff looks like it needs addressing then you address it.
Axis/Vegas comparison (note the headlights):