The biggest problem that you may have is an electrolytic reaction between the Stainless steel and the aluminum.
This is off of the Reynolds Aluminum foil site
1. When aluminum and a dissimilar metal are in contact in the presence of moisture, an electrolytic reaction may occur causing a breakdown of the aluminum. To avoid this use aluminum, glass, ceramic, plastic or paper containers. Do not cover sterling silver, silverplate, stainless steel or iron utensils with aluminum foil.
2. A similar reaction may occur when salt, vinegar, highly acidic foods or highly spiced foods come in contact with aluminum foil. The result of these reactions is a harmless aluminum salt. Some aluminum salts are used in medicines to treat stomach disorders. The food can be safely eaten; however, the aluminum salt particles can be removed from the food to improve the appearance of the food.
Now I will be the firstto admit our rigs skin is thicker than foil, but the process will still occur when moisture is present.
If the holes are normal rivet sized you can get pop rivet backer plates that are alumimum and use them as a washer. Use a longer than before rivet, alumimum as well, and then this cannot happen.
I belive this is why there are regular steel screws where ther are screws in the skin.
Let us know what you decide.
WBCCI #5501 AIR # 49
1978 Argosy 28 foot Motorhome
Wise men talk because they have something to say; fools, because they have to say something. -- Plato