Absolutely. I recently bought an Aerodyne Jazz Bass, with position markers on the side of the fretboard only. I was was worried that it might be a problem, but turns out it wasn’t.Position markers on a fretboard are there for the audience to see. Unless you're hunched over, you won't (and therefore shouldn't) see them while you're playing. But on the side of the neck? Go for it:
View attachment 4439109

