I need to replace two rivets on the drivers side Handrail of my 2005 Cougar-What size rivet are they? I am assuming they are aluminum 3/16" head ones, but dont know the length?-Can I easily replace these with a hand pop gun? Should I drill any remaining piece I see in the hole?-Where can I order some. I dont need a huge quantity, although if they are universal throughout my boat, I would mind having extras? Thank you.