The Un-Bolted Doll's Head in combination with a Double Underbolt is not indicative of a Lefever, though I could not state "Positively" he never made one that way. The 4Dram-1¼oz would seem to indicate a 10ga though the 11 could indicate either an undersize 10ga or an overbored 12ga. Since this was not a mark applied by the proof house but would have been the maker's it could have been applicable to a 12ga chambered for a long brass case.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra