From what I've read over the years, by then the newly introduced JAMMA system was already in play. Stands for Japanese Amusement Machine Association as I'm sure you already knew. So they basically ran around this idea and they used mostly generic candy cabs and just about all games have come in kit forms since. Sega made Many over the years, but back then, I think capcom and Pony or a bunch of others I can't remember off the top of my head produced most of the "generic" cabs then like TBK said.
Operators would and still get kits and swap out a game into these "blank cabs". In a kit you would get:
1. the game marquee
2. PCB
3. maybe buttons
4. button cappers, or joys if needed, and a
5. CP marquee instead of bezels.
Marquee bezels were just strips that went along the CP marquee inserts. On them were brief instructions on how to play with maybe a bit of artwork. Japanese have always been a lot different then we were. The marquees were mostly magazine type looking advertizements with some also having some instructions on how to play the said game. That is one thing I thought we have always done better.
I don't think Japan used bezels or side art at all back then or even now. So the original FF kits in Japan only included PCB, marquee, CP marquee and a special pop up thing pictured below. The way the cabs are designed, once in a blue moon a cab will get side art. But those are those giant games like HOD, or TZ etc. Space has always been limited there so games never stood out alone really, they were always lined up close making side art useless. Some cabs got their own company logo on the side. ie: Sega Blast City.
This thing is super rare to find. Many times a game might get these posted on or around the cab.
A generic Japanese candy cab (BUT OF GREAT QUALITY!!!) as different games.
Also BTW. Some games like SFII did get custom CP's. Not sure if they were official or not, but I have seen some.