I am the same way (except for the missing pinky). I write left handed so am considered a lefty, but I’m all over the place. Throwing a baseball or football overhand I do lefty, yet shooting a basketball, throwing a frisbee, golf, hockey, swinging a bat all righty. It is kind of ambidextrous, because I will likely be better at something with my off hand than most people are with their off hand, but there are very few things I do well with both… there is always a dominate hand for each activity.
That all being said, I’ve never had any luck playing bass lefty, righty is natural for me there. I would say if righty feels more natural to you on the bass, you should stick with that even with the disadvantage of the missing pinky. Like others said, you will just need to get better at shifting and do more of it than most of us.