Yes that is a 3M tape designed to attach metal to metal, once it comes in contact with the surface it is not coming off.
I used this to bond my SS to the sides of the RV and you better be sure you have it right the first time or your bumming.
Great photo's Patrick, I think the way you did the cab will make life real nice getting in and out from the motorhome section.
2003 28' Show Hauler Motorhome on a 1995 FL 120
www.showhauler.com