The easiest way to answer is from one of the code books themselves.
So, take D1.1 and go to Clause 1.8, at least in the 2006 which is in front of me. You have the US Customary edition and the SI (Metric or 'M') edition.
For all of the AWS codes and standards the 'M' designates the use of SI in brackets thus incorporating the two versions in one copy.
So all codes currently come as: AWS D1.1/D1.1M:2010 for example. Indicating both measurement systems.
NOT MILITARY. Someone needs to do their due diligence before getting you worked up over nothing but old wives tales. No military versions here. Those are totally different codes, applications, and publications.
He Is In Control, Have a Great Day, Brent