1st question-Is the flaperon fabric covered or just primed and painted?

2nd question-The instructions say to rivet the aft edge of the flaperons with 3/32 x 1/8 rivets (part 95001.000) which I did. When I used my hand riveter, it leaves about 1/8 of the rivet protruding on the bottom side. This does not seem right. I would think they should be pulled as flat as the top side. Am I using the wrong rivet? The instructions say that I could use the solid counter sunk rivets, but I am trying to use what KF sent to keep my cost own. Any thoughts appreciated.