Fender mustang 1977 - original or replacement pickups

The wiring doesn't look especially 'factory Fender' to my untrained eyes. The uninsulated ground strap is unusual, as is the two pots that appear to be different ages and/or manufacturers? The Strat knobs appeared on Mustang basses circa '76/'77, presumably when Fender moved over to splined split-shaft pots.

The pickup doesn't look like a '60s Mustang pickup, as these had shorter magnets and a blade in between them. It could be that Fender revised the design by the late '70s (wasn't 1977 the last year of US Mustang bass production?). Using the same colour of hookup wire for both ends of the pickup seems to be a bit un-Fender-ish as well. The difference in colour between the white harness wiring and the white pickup wiring is also a little unusual?