I am replacing my smoke/heat/freeze detector and not sure if I need the e-series or regular. Furthermore, I don’t know what model of controller I have. Hoping for some help on both of these related issues.

According to records you have a regular 2GIG GC2.

When in doubt look at the model number of the device you are replacing. If it is not an e-series 2GIG sensor (with -e at the end) then do not use e-series replacement.

E-series sensors are encrypted versions which only work with the newer E-series versions of the 2GIG Panels.