If the ROM files haven't changed then they will work fine. Something like "golden era" games like Donkey Kong (dkong.zip) would probably work from a newer romset as there hasn't been many changes over the years.

Three things may change. They may change the name of the entire zip file, they may change the name of a ROM inside the zip or they could change the content of the file. Meaning it's named exactly the same name but it's a redump of that ROM. Any will render the game unplayable. So even a newer romset is no guarantee you can use a ROM verification program to get a complete earlier version (i.e.- 0.37b5 or 0.106) as the file may not even exist except in older versions.

MAME is pretty specific in how it works. It's looking for exact zip files with exact ROM files in that zip. If it can't find them it fails to run.

Your best bet is to use a ROM verification program or you can just dump them in the correct subdirectory and see what plays and what doesn't. I have seen some that fail the ROM file check but still run, like King of the Monsters 2 (kotm2.zip). Maybe I never made to the level, whatever sequence or event that would completely crash it.

For the most part they will probably not run without the correct files but it's always worth a try if you feel like it.

@Chad - "It's looking for exact zip files with exact ROM files in that zip. If it can't find them it fails to run."

Agreed, but I have altered some ROMs on MAME4ALL, only difference was that you would get "The game may not run correct." and wiggling my joystick from left and right will continue into the game and altered ROMs effect would be there in mame4all.

I think MAME isn't looking INTO ROM itself. It's only looking at memory, name, and lot of other numbers data. But, I'm not absolutely sure.

I've attempted to mix Ms. Pac-Man and original Pac-Man roms together and end up with a weird version of Pac-Man on MAME4ALL, but still neat, though.