You are certainly lucky! Had there been no signature interest would have approximated absolute 0. At least you now know you had an Indiana made gun.
Miller, B. T. (1823-). gunsmith. 1855-70, Tipton, Indiana; 1884, Fayetteville, Arkansas. 1880, B. T. Miller, gunsmith, 57, born in KY, both parents born in VA; M. J., wife, 41, born in KY; Julia, 21; Susan E., 18; Olley, son, 16, all children born in IN [Census; Lindert].
I could not verify the VERY late directory nor is Miller on the State of Arkansas list. He was listed by Lindert in his book on IN gunsmiths.