I'm generally not a great fan of natural look bass fins, but a natural korina Explorer has always been the exception. Maybe because when Explorer guitars became more visible in the mid-seventies for the first time (only very few were produced in the late 50ies - much fewer than, say, Flying Vs which also stemmed from Ted McCarty's initially failed "Modernistic Guitar" series), the natural ones were the most prevalent - with the natural wood look and the radical shape making an unusual, yet iconic combination. Allen Collins (who had a penchant for asymetric guitars, he also played a Firebird) of Lynyrd Skynyrd was really the first guy I took notice of who played an Explorer guitar.
On bass, it was Martin Turner of Wishbone Ash with his black Hamer Explorer a little later. Given how incessantly WA toured the States (even taking up residence there) in the mid-seventies, their paths must have crossed with Lynyrd Skynyrd quite a few times and I wouldn't be surprised if Martin saw Allen's Explorer and decided to have one made for him as a bass.