Generally, yes. The a/c package is listed as "Optional" which means you can put one in. You just need to get the mounts, ac compressor, lines, radiator, "cooling block" (the part thats actually inside the cabin circulating a/c coolant), etc.
I'm not the guy to talk to about the whole process, but I figured I'd at least try to move you in the right direction.
Also, junkyards. Look for 01-03 civics and try to salvage the a/c parts off of them. WAY cheaper.