In a word, yes
Technically Oceanside is dispatched on 3A and uses the 3* talkgroups for responses and tac. 3A is basically perma-patched with 4A and 5A (like 3B, 4B, and 5B) so you'll get all of the dispatches for NorthComm, but 3C through 3P are used for the "coastal" departments like Oceanside, Carlsbad, Encinitas, Solana Beach, and Del Mar. They're often patched with 4C-4P and/or 5C-5P (but not ALL the time, like the dispatch and admin TGs) so don't be surprised if you hear regular runs on the 3* TGs
The Wiki has more detailed information on stations and whatnot.