Pedantry isn't so bad, if it's correct... As was stated, the term "source codes" is very common in many communities, particularly scientific computing and associated academic circles. The only credibility lost here is... well let's just move on here, shall we?

The guys at Los Alamos were talking about "codes" (programs) before you touched a computer (and yes, I looked at your profile, I know you've been doing software for 25 years, but there's more to the world of software than mass-market applications)

"Codes" is common in some sub-disciplines (eg HPC). Still sounds weird to my ears though.

Codes is the normal word in Mech Eng, at least, and in other disciplines that were early adopters of computing.