Wal MKI 1980-82? natural mahogany

WAL MK1 CUSTOM bass guitar.  This is a beautiful and comfortable-playing bass with tremendous sound quality.  All electronics work perfectly.  Schaller tuners, Mahogany body, and (presumably) rosewood fretboard on maple neck.  
This model was apparently an early, transitional model such that the MK1 body and electronics (pickups included) were joined with a neck showing a more Pro model headstock; however, it's headstock is marked "WAL Custom Bass."  
The only difference from the MK1 spec is that the body seems to be a solid 1-piece (no facing, just beautiful, streaky mahogany.)  The laminate work is very intricate, with walnut, mahogany, or rosewood laminates through neck and also through the body.
The early WAL basses— this one included-- had some finish issues, which accounts for the white streaking that occurs on the back side of the body.  The front, however, is not affected.  
The bass has LOW action with great sound.  Currently strung with Rotosound Funkmaster 30-50-70-90 strings.  
I contacted WAL factory, and showed them the serial number on the plate (PB— indicating, I suppose, a Pro Bass part) and they had no record, but said that is not unusual for the early models.  This, being a sort of prototype, doesn't track back in record but is the real product.