Ron,
They do not come with double-sided tape, but I suppose you could use tape. Mounting it with screws is not a problem as if you remove it you just seal the holes with white silicon sealer. Cosmetically you can see something was there, but functionally it is as good and secure after the fix.
If they are mounted where mine are, for the most part they are out of the major water zone. Plus, I am not sure how strong double-sided tape is. Hope this helps. Also, for info on the rails on the wings. The bottom of the rail is probably 1/2 inch tall and is hard against the fabric on the wing, so I think placing coins, etc. up there would be no problem.
Bob