looks like a bootleg, it says PACK MAN on the label
Maybe its a converted galaxian board with a sticker on it?
It's not a galaxian board. Galaxians have numerous chips perpendicular to the others (Graphics roms and some ram chips)
That's an authentic Bally/Midway Pac-Man board. It just has the Namco custom 284 and 285 chips in place instead of the daughter boards for the SBC and VRAM controller. (B/M switched to the daughter boards when Namco couldn't supply enough custom chips). Remember, Namco designed Pac-Man and simply sold the U.S. rights to B/M.
The reason the sticker says "PACK" is because B/M seemed to have horrible spell checkers. Every authentic cabinet I've seen with the original dip switch setting card also says PACKMAN and have seen this sticker on about 1/2 the boards. In fact, as posted in another thread recently, they even frequently misspell GALAXIAN as GLAXIAN on their service bulletins.
You can replace the large daughter cards with these custom chips on any board, and you can order repro custom chips from JROK and others that fit exactly flush with the board if you dont have or dont want the daughter boards.
BTW--Some would think your board is a bit more valuable, as it's rare to find these chips, especially both on the same board. The custom chip for the SBC (next to the Z80) is more common. The VRAM chip is a lot less common.
However, most others would probably rather have the daughter boards, since namco custom chips are well known for having thin and brittle legs that tarnish and break off. However it's a lot more likely to accidentially bump out a daughter board and then have someone put it in backwards and destroy it as well.
So in the end, it's just probably an earlier build of the board, nothing special at all. (look for the actual serial number imprinted on the top of the large rectangular ceramic resistor by the heatsink and 2 caps on the upper right of your picture..--some have it printed there, some have washed off or didn't have it.) Actually I think I see it's either 0424 or 9424, either of which is low. Most boards I've seen are in the 15,000 to 45,000 serial range I think.