Yes, stampable UV is required when foil is used on top or the foil would flake/peel. Good thing you did your research. For the past couple of years,in situations where we have we have both Matte UV and Spot Gloss UV on a job, we are flood-coating the sheet with Gloss UV on our coating unit using a coating blanket, then overprinting a spot Matte UV using a plate on a second pass. Prior to that we were using a flood coat of Matte UV (plate) and then using a cyrel plate to apply a spot Gloss UV on the coating unit. You could get everything done in 1 pass this way, but the cyrel plates were a pain to work with, expensive and hard to register. The newer 2 pass method works out cheaper and easier for us in the long run.
Here's one, do you trap your UV?Just found out today, my UVer makes it work, but wondering how it's done.