Yes, I've seen it in Chevy and Ford rods as well. Sometimes just on the small end and sometimes the big end, then the whole rod at times. According to some GM engineers I've spoken with, it was to keep from scraping rods that were bored too big on the B/E or S/E and otherwise being non conformance per the specs as 66fs mentioned. Just like the Maltese Cross stamp on many Mopar blocks denoting an odd oversize bore or rod journal size. Any attempt to keep the production moving forward.