We visited the Winnebago plant in Forest City this fall and watched the Class A and C wall assembly line for quite a while. There were no studs per se. Once the exterior fiberglass wall is laid down and the Styrofoam layer is glued to it, it goes to the next station were a laser projected from the plant ceiling projects lines exactly where metal strips for anchoring cabinets, wall mounts, etc., are to be laid out according to the specifications of the specific rig the wall is being built for. More glue is sprayed on, then the wall section goes to the next station where the interior panels are laid on. After that the entire assembly goes through a set of large rollers that presses everything together.
Didn't see most of the rest of the assembly line but judging from my 27Q the interior walls do appear to be framed with 2 x 2s or 1 x 2s.
I highly recommend that factor tour. It is really interesting and informative.
2016 Minnie Winnie 27Q on a 2015 Ford E450 chassis. Retired U.S. Air Force. Living in Anchorage, Alaska