Wow, nice find. It says manufactured by Dyanamo, so it still smells pretty 3rd party to me. I wonder if the original purchaser bought that from Capcom or Dynamo? Would make sense to make use of any cabinet design you had on hand to churn these out as they were so hot at the time. I'm curious what the plate on the back of a dedicated Z-back reads.
It actually says "produced" by Dynamo, which in legal terms is different than "manufactured" I believe.
Dynamo printed the name of the game on the label, so it was an official deal between Capcom and Dynamo (Capcom shipped Dynamo the necessary materials [boardset, art, etc.] and Dynamo did the rest). SNK made a similar deal with Dynamo for Ikari Warriors (HS-1 cabinets), as well as Victory Road, Guerilla War, Ikari III, etc.
Another interesting thing is that the game was originally to be called Street Fighter 3 (or it may have been a working title, like they often do with movies), which is reflected on the label.
I remember back when I first started playing SFII in the arcade (around '92), I saw a contest in a video game magazine to win a brand new SFII CE machine, and it was in a Dynamo HS-5 as well.
As you mentioned, the SFII CE conversion kits didn't come out until later, forcing operators to buy new machines if they wanted the hottest game in town in their arcades. There are some old newsgroup postings from that time frame where operators are complaining about that bit of "extortion" from Capcom. Also, to add fuel to the fire, Capcom falsely claimed that there would be no conversion kit available, thus increasing the incentive for operators to buy new machines.
Capcom has never been a cabinet manufacturer for U.S. games that I know of; and neither has SNK. In fact, most of the Japanese companies worked in this way for U.S. releases with the exception of Nintendo, who set up "Nintendo of America" who manufactured cabinets, plus they imported quite a few Japanese cabinets as well. For example, Namco teamed up with Bally Midway; Capcom teamed up with Romstar, Dynamo, and maybe others; SNK teamed up with Tradewest and Dynamo, and maybe others; etc.