No.
I think their "conversion class" just refers the hardware specs, not board compatibility (though I could be wrong).
Galaga was licensed from Namco, by Midway for North America, while Dig Dug was licensed by Atari. Those companies designed their machines differently. And then if you're from europe or elsewhere, there's other manufacturers involved too.
So... No, not likely.
(but someone more knowledgable should chime in)