It is Lemmy's own bass (allegedly, but why not?) the outline is slightly obscured by the strap hanging over it. I'm not a Rick afficionado, but I guess it was customised to what he wanted (three humbuckers, gold fittings), as opposed to the signature model which is, as you rightly point out, more decorative, but a distinctly different instrument.
As I was trying to find out where the bass came from I discovered that if you want a 'knock-off' Lemmy bass from Ali Express it will set you back a grand total of £413. Fine if you only want to hang it on the wall I suppose.