HP 1000 M series on Ebay

I noticed this the other day... I'm a bit confused as to it's lineage. First, the M series has a unique keyswitch, unlike the E and F series. In the E & F, the keyswitch is nothing more than a latch to open the front panel. On the M series, the front panel switch is electronic, selecting R (reset memory I think), Off, Standby, On, and perhaps Lock (going from memory). The one on ebay has no such markings on the front panel. This would make me think E & F. But the front panel is clearly from an M, as it only has the ABSTPM registers, not the special register mode (index registers, etc.). And in some of the pictures there are two pictures showing behind the front panel, and to me at least, it looks very non-HP (custom) with regards to the cables coming off the front panel board, and some kinda (non-hp?) board underneath that. Wierd. Not to say it isn't a fully functional M series, but... I have never seen one quite like that. Regards, Jay West