Mark King did have a Fender signature model for a minute. Only a few dozen were made - they couldn’t hold up under regular use when he took them out on the road. He was seen playing a British Goodfellow Jazz style bass prior to the Fender. Might have been a prototype?
King is pictured using a TC Electronics rig here. The Fender Mark King bass predates the introduction of that amp by many years, so this video is relatively recent. I don’t think he’s playing a MK Fender here - Those had a slightly non-standard headstock shape and body shape. He’s been using a little more organic and less high-tech sound over the last few years, but even then he’ll change it up sometimes. The Jazz he’s playing here is probably one of those experiments.