It is indeed a photoshop, and my guitarist made it
I had replied to his email with something like 'Hm, it looks a bit photoshopped, the bridge looks funny, the neck laminates look funny and the B-string above the nut looks funny'. He replied with 'Hey, don't diss MY photoshop skills!'
Peter, you're right, this isn't based on a picture of the original 1978-1981 MC924. It is based on a real bass though: There briefly was a reissue in 1995 or 1996 with those closed pickup covers and control knobs, and pearloid tuner knobs. Aside from those details, it was based on the early eighties-version of the MC924. But there was no lefthanded version.