Jerry; I have a 1954 vintage 2" O.P. They were made on special order in the late 1930s with 2",but not catalogued,as they were after the war. The "war finish Commando",was also made in 2" during the war(along with 4") and some 4" were rebarreled after W.W.Two to 2",but the new 2" bbls had more of a ramp back face on the front sight. The round butt,was a special order,prior to the war,but most 2" guns were shipped that way. The NYPD(and Ive heard some others)had special ordered round butt 4" sent for use by plainclothesmen. To really screw the issue up,the very rare Colt Marshall,circa 1954,and so marked on the barrel,was an O.P. in every way,except it had the rounded butt in both 2" & 4". It took me a long time to find an original 2" O.P. in excellent shape(but my wife took it to use in her purse!). Id be wary of ANY round butted O.Ps.even if Police Dept. marked,without a factory letter or at least provenance(proof) thats its "all original-as shipped". Bud