Hi Brett,
I would trust your own experience about which one feels firmer to you but even if they are the same firmness they would feel different from each other. There is more about how innersprings compare to a latex support core in post #28 here.
The relationship between firmness and support or alignment is often misunderstood and many people believe that firmer is “more supportive” which isn’t always the case. A mattress that is too firm for a particular body type and sleeping position will provide poor support under some parts of the body and a mattress that is too soft for a particular body type and sleeping position will provide poor support under other parts of the body. One of the two main functions of a mattress is to keep you in good alignment in all your sleeping positions and this needs a combination of good primary support under the heavier parts of the body and good secondary support under the more recessed parts of the sleeping profile. There is more about primary and secondary support and their relationship to neutral alignment and pressure relief in post #4 here and in post #2 here.
Phoenix