Thanks!I think the pickups in those SR's are Ibanez made. The routes should be compatible with MK or P2 size pickups. P2 i s what you will find for most high quality pickups from brands like Nordstrand, Aguilar, Bartolini, Delano, etc. Trouble is, most of those options, new, will cost more than the entire bass.
I have some Carvin pickups for sale, which are P2 shape. Check the link in my sig.
I am not too concerned with buying used quality pickups......its sort of like buying used decent PAF types for Gibsons, they are generally easy to flip if need be.....at least that is what I am guessing
Otoh, as I mentioned, I have little experience with swapping bass guitar pickups other than some P bass types.
It sounds like there should be some used PU options for this SR300...any favs overall?