Yes it can be done. Gas line, 12v
, and 120v electric will all likely be added or moved as well as the cabinet work. Not a giant deal to do but not an entry level job either. JC can make it look like new.
Before you go too far, check measurements above where you want the oven. Usually those have a stovetop and some have a solid flip up top, some are bi-fold tops that need less clearance. In the Classic, the microwave is not over the oven but beside it due to clearance as well as venting. With a stovetop/oven you will need a vent to the outside most likely. If you don’t have one of those already (some microwaves mounted over a stand alone stovetop vent outside, some just move air inside).
Venting, to me, is the bigger issue if you want it Classic-like. I completely understand the oven desire. We have a Classic and love it (both oven and micro). We also have a 2005 land yacht with no oven, just the convection, for now. The convection micro does work like people say, we have baked in it. But we love the oven in the Classic.
To get it all done by someone, I would guess $3-$4 grand. I am thinking $150 and hour. 2 days for lines and cabinets, half a day for venting, $500 for the oven. Half a day to install and clean up. That is a wild guess and might be low or high. But if you want the oven, you probably won’t be happy if it looks hacked together by Curly, Larry and Moe. Call JC and get a guess from them.