Smooth firewall question

[FrankenChevy]

I'm about done with smoothing the firewall on a '67 Camaro. I've butt-welded panels in the a/c hole(s) and I started to worry that I just might weld one up that I'll eventually need (not too big a deal...just more of a pain in the rear than anything). I plan on putting in an aftermarket a/c (Vintage Air or something similar). I've attached a pic with the holes in question numbered. I know that I will eventually have to drill some holes for the bulkhead fittings but I want to locate and drill these later when I get a better feel for where I would like them. I think all the holes numbered (1 thru 5) need welded up along with all of the holes remaining in the outer righthand cowl. Is this correct? Any help is appreciated.