The dealer ordered me a set today. They are $12.51 per side and must be prepaid before ordering. Don't know about shipping since I will be picking mine up.
As far as being dot approved They have the dot on the lens itself. The only thing different from the truck lenses is the back up lens that is glued in is made of red plastic instead of clear. The chrome trim ring can be removed from your old lights and attached to these ones.
RV Traders in Mesa AZ is where I got them. Talked to Russ in the parts department. 480-464-9724. Tell him you need part #s 100004 and 100003 for the Keystone Montana 5th wheel trailers.
www.rv-traders.com