Mike,
This is one of those things that, it would be nice to see some previous work that has been done by the same "craftsmen" that will be doing the work on your intended coach. It's like getting an estimate from a construction contractor. You'd like to see what kind of work that contractor has done in the past and, if possible, talk with some folks that have employed that contractor.
So, in this case, if you possibly can see previous work, and it appears to be good quality work, then that will help you make that decision to go ahead with the deal and modifications. But, if on the other hand, the dealer cannot provide any examples of previous work done by the techs that would be doing yours, then that might make the decision a bit harder.
It's always nice to see work that's been done and you can evaluate it. Good luck,
Scott
Scott and Karla SDFD RETIRED2004 Itasca Horizon, 36GD Slate Blue 330 CAT
2011 GMC Sierra 1500 Ext Cab 4x4 Toad
2008 Caliente Red LVL II GL 1800 Goldwing KI60ND