CID/MID has nothing to do with roms, the only time this comes into play is if you are trying to OTA or RUU back to stock, RUU and OTA check the CID/MID and determine whether or not the model is compatible with that particular OTA/RUU... As for modems, generally roms do not include radios/basebands, most roms are just system/boot, if a radio is included it is more then likely stated in the Devs OP, also with S-Off its easy enough to fix radio issues should you run into this. As I said the ATT variant is based off the international and gpe variant hence any rom will work.
One Plus One Sandstone Black 64GB
LG G3 D851 SIM Unlocked (ATT) 32GB
HTC One M8 32GB Gunmetal Grey
LG G-Pad 8.3 GPE
Google Nexus 7 16 GB (2013)
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