Gibson never officially used ash, but would they have cared if they had it stocked at the time? Of course not. It was a preferred Fender wood and construction-wise Gibson was emulating Fender with the Ripper more than ever. If seventies Jazz Basses used ash what should have kept Gibson from doing the same? No one gave a damn at the time what a Ripper was made out of just as long as it wasn't mahogany (to set it apart from its "too dark-sounding" predecessors).
That wood looks exactly like the wood on my SB-350/450 - basses that came out around the same time as the Ripper. I always assumed that to be alder, but I suck in telling alder and ash apart except via the weight test (and of course, too confuse matters further, there is light ash too).