It has been a while since I've owned either, but I have used P-85, 89, and 95 magazines interchangebly in the past. Ruger shows different part numbers and the baseplates may be slightly different. Seems like they have used different followers on different guns, but I never had a problem. Things may have changed with newer P-95's but I doubt it.
It is sorta like the different generations of Glock pistols. Glock never changed the name of their guns, just called them gen. 1,2,3, or 4. They have made several changes to their magazines as well, but other than the guns with ambi mag releases they will all interchange.