if you don't see the big block with copper windings then no, it's not an isolation transformer. as an example, Midway switched to something similar in the mid-90s and very frequently people install monitors that require isolation transformers (like the WG K7000) and they typically come here saying "my monitor got blown up" or something similar cause it's not an iso, it's just an AC distributor.
I'm fairly certain those cabinets shipped with Wells-Gardner U2000s from the factory, since they were standard resolution games. the U2000 does not require an isolation transformer, which more than likely points to you not having one in that cab.
going with my Midway story, that's because Wells-Gardner started making monitors that had their own switching mode power supplies on-board and thus eliminated the need for isos, and the manufacturers followed suit. Sega wound up doing the same I guess.