I checked the IL. regimental histories and none of those,46th,50th,101 or 120th were near Murfreesboro Dec.25-31.I still haven't located my notes!However the 120IL. served as Provost and Garrison Duty at Ft.Pickering and latter Memphis,Tn.in Jan. of 1863.I'm not sure what a GBPvt.is.I don't recall if Vicksburg was still a exchange point at that time.It is conceivable prisoners could of gone through Memphis.