Strange on this.
Before this list, back in 1981 I owned a white m400 which I bought with the cabinet in pretty poor shape. So i hit on the idea to carpet the outside in an unusual industrial blue. Edging the corners and sides with alloy/plastic strip.
Could be a coincidence, or more likely, I think that unknowingly I let this historic machine through my grasp when I sold it a couple of years later. Had no record of the serial number either. Damn!
Andy K. Serial number Andy 2 (you were here first Andy T)