Practically all phones have separate application/baseband processors, since the baseband processing has hard realtime constraints; I think what you're more interested in is whether the baseband CPU has direct access to the main memory and CPU, and that's not something that can be discerned physically. Even with physically separate baseband/AP CPUs, the former might have DMA access to main memory.

Off-topic, but I couldn't help pointing out that saying "DMA access to main memory" is even worse than the classic "ATM machine" or "PIN number."

Since we're nitpicking, no it isn't. DMA is a particular method of accessing memory. You can have direct mapped access, cache mediated, PIO, DMA, etc. There can be many different memories, such as expansion cards, where you could DMA to/from, apart from main memory.