This looks to me like it was, as Macdrone notes, a nicely upgraded-to-512ke specs-but-dirty-and-neglected unit that some L@@K STOVE JORBS!!!! eBay nitwit tried castrating back down to a stock 128k (despite completely not knowing what he was doing) in order to increase the perceived collectors value. To my knowledge RAM is *never* socketed on a stock 128k and all that piecework with the jumper wires is undoubtedly the hack to enable the system to work with 256k chips. It ain't going to work right as a 128k unless you remove that mod; before doing that I'd suggest at least trying to pull out the 4264s and replacing them with 41256's just to see if the board will run correctly as a 512k(e).

And, frankly, per the above, if it works as a modded-up 512ke I'd suggest leaving it like that. It's far too butchered to pass off as a pristine "collectors item" and it's a far more *usable* machine in the expanded configuration.