Remarkable "Pine Creek Dave pre-production special order" BTFE
Dr Bob could no doubt help re: Lefever but the earliest
double gun (not SBT) BTFEs were:
Hunter Arms 1920 as part of the "Trap Package"
Baker Expert Grade and Paragon Double Barrel Trap Gun with the "Baker Perfect Grip" Fore-End c. 1921
Parker 1923
Ithaca 1925
http://www.doublegunshop.com/forums/...&Number=487249
Scroll down here for Dave's special order one-of-a kind 1901 Smith BTFE, according to his grandpappy, Bill Brophy and George Bird Evans
http://www.16ga.com/forum/viewtopic.php?t=23107&start=0