DMD = any machine with a DMD. Not an alphanumeric (Funhouse) - even though it is a WPC.
SS is anything from 1978 ish to Funhouse.
Operators NEVER bothered with code updates at the start of the DMD era. They simply didn't exist on Bally / Stern / Williams. What left the factory remained the same. There were changes on DMDs - ST TNG comes to mind as a very buggy game when it was released because the rules were so deep. Cactus Canyon is the only title where there was seriously unfinished code. But no game in this era left the factory with unfinished code. That's issue has only just started recently with Stern (and now JJP). I think we will see games produced with unfinished codes, but perfectly playable - AC/DC is an example. What Stern are doing is they are trying to improve the game by accepting feedback from operators and home buyers. I don't see this as a bad thing, because cost cutting by Stern in the mid 2000's meant that once a game was finished, no more development $ went back into improving the software, or attending to any bugs. The book was closed for that title UNLESS it was affecting earnings. So I see it as a good thing that Stern will revisit code on new releases, as they are receptive to feedback. What I don't want to see is the deliberate release of a title with unfinished code to beat the competitor to the next release. I accept teething problems and revisions, but not wholesale changes with 100 fixes..