Sorry about taking so long to reply. This is likely no longer an issue, but you ask a good question.
My awning rails are drilled right through the Ensolite. If I drill out the rivets, the inside part could be retrieved with tweezers. If your Ensolite has no holes, then it's probably OK to leave them, unless they look terrible. Then I would cut a small incision and pull them out. Then get some paintable calk to cover the hole, if it showed at all.
