In the manual when it say interior (SPKR) vs exterior (OUT1) siren, the SPKR terminals are for connecting a speaker-type siren that takes an oscillating input signal and OUT1 is for connecting a piezo siren that takes a 12VDC input signal.
OUT1 can also be used for other things that take a 12VDC input signal such as a strobe light. Or if you have some kind of light that indicates when the system is armed, OUT1 could be powering that. I doubt OUT1 would be powering a camera because it’s only on in certain programmable conditions, like when the alarm is sounding or the system is armed.
If your siren was wired to the SPKR terminals on the concord then it won’t work with the Hardware 16-F. The 16-F only works with piezo sirens, like would be connected to the OUT1 terminal on the Concord 4. You could get a 12VDC speaker driver and add it to the speaker-siren you have or you could replace it with a piezo siren.