bandwidth

What bandwidth do "bubble pack" radios use to transmit on the interstitial channels 1-7? All the bubble packs are combo GMRS and FRS radios these days, and unlicensed users can transmit on the shared interstitial FRS / GMRS frequencies (usually channels 1-7) as long as they have their radios set...

Do I have to set the bandwidth to 12.5khz when programming P25 channels to this radio or when I choose digital mode for receive and transmit will the radio force 12.5? I'm assuming the bandwidth selection is for analog only...am I wrong? Thanks!