Steel Rivets in Milsurp Holster
 

I picked a couple of these up for my CZ-82, and want to wet mold them to my pistol.
http://www.sportsmansguide.com/net/cb/cb.aspx?a=414740
I noticed the rivets are steel, and before I mold the holster I'm wondering what I should do to protect the finish of my gun?(paint) There are no raised edges on them or anything. Should I just coat them in nail polish and forget about it? Do I need to replace them with brass?