Springfield did not annotate on their records which guns were carbines and which were rifles as the serial numbered part, the receiver, was common to both. There are ranges of serial numbers associated with carbines but were actually rifles so the serial number is not a definite identification for a carbine. The true measure of a barrel is, with the bolt closed, using a cleaning rod, a carbine should measure exactly 22" from bolt face to muzzle. Rifles that were cut down to carbines were often not cut excatly to 22".
There are lots of "FrankenKrags" out there (I have one). Don't be discouraged, they are still fun to shoot and a part of history.