The sealant used by Monaco was Acryl-R made by Schnee-Morehead. The product number is SM5522. I think th e company now is different you can find info at acrylr.com.
Steven Link
I bought several tubes of that from Monaco parts when the coach was new and I had read that Monaco recommended resealing the roof annually.  It was a pain to use.  I ended up using Camping World's Dicor Self Leveling Lap Sealant instead.  
The easy and fast way to get the old stuff off is with a vibrating saw that has a putty knife blade on it.  Mine is a Rockwell Sonicrafter, but there are lots of brands.  The last time I did it, I got both the front and back roof to cap seams cleaned and sealed in under an hour.