I checked the USGA website and it says that the 735's in chrome conform to all the current rules, but the stainless version has yet to be approved because they haven't done enough testing.
Don't both versions use the same grooves? Why would one conform and the other not?
I'm curious because I have the stainless version and would like to start playing competitively. Not sure how many tournaments I'll enter that are concerned with that much detail, but I'd like to know in case it comes up.