emailed preferred barrels because their website didn't list it..... and they said no, that the CTR and the T3x are cut different.... and others just say Tikka Prefit. doesn't mention if it will work both ways. but when you go for a chassis (KRG) you have the option for a CTR mag cut or standard T3x and AICS mags..
Really, because PBB list as making them?! And yes, they are the same because the CTR is the T3x action. Tikka even has it listed under there T3x menu. Now the Tikka T1x is different from the T3x, and that is maybe what PBB thought you meant.
As for the KRG stock, you can either go with factory mags or the AICS type. If you already have riles that can take the short action AICS magazines, you could save money by going with that chassis.