Thanks for all the input! I just got back from running all over town trying to find some 3M windo-weld. Finally found it at AutoZone, for the ridiculous price of $20 for a tube. I looked at Menards, Fleet Farm (Farm and Fleet for eveyone else), Advance Auto Parts, and O'Rileys, all of which didn't have it.
The spare mounts that I have are drying right now, and I will give them a once over again with a toothbrush... can't be too safe. Once these go on, the old ones will be getting the same treatment.