It is possible that only the lock was made by Dreppert - there are many others that have a deeper knowledge but in my opinion I would not rush to restore this piece - I like it just the way it is.
This was always a smoothbore based on the butt plate and side plates and the octagon to round barrel - IMO
Below is some info for your consideration
Andrew Dreppert (1806- ). gunsmith. The tax lists of 1826, 1827 and 1828 are missing. In 1829 Andrew Treppert, freeman locksmith, appeared. In 1836 he was first called Drepperd. In 1847, 1848 and 1852 he was taxed as a smith. In the U.S. Census of 1850, Andrew Dreppert, gunsmith, gave his age as 44 years. In the U.S. Census of 1860, he was still listed as a gunsmith, but gave his age as 50 years. His shop was located on W. King St., corner of Mulberry St., Lancaster city. [tax; Boyd's Lancaster Dir., 1857.]
Christian Drepperd (1861- ). gunsmith. Lancaster city. [U.S. Census of 1880].
George Dreppert (1787- ). gunsmith 1849, Lancaster city. [tax].
Henry Dreppert [Treppert]. gunsmith. The name of Henry Treppert, gunsmith, was carried on the tax records be¬tween 1829 and 1840 in Lancaster city. The tax list always listed him as "Treppert." His guns are marked "Drepperd."
John Dreppert [Treppert] (1787-1864). gunsmith and gun lock maker. John Drepperd's shop was located at the corner of Mulberry and King Sts., Lancaster city. From 1810 through 1813 he was called a locksmith and his name was spelled Treppert. In 1814 he was taxed as a gun lock maker, and that listing continued through 1825. The tax lists of 1826 through 1828 no longer exist. From 1829 through 1840 he was taxed as a gunsmith. Tax lists always spelled the name "Treppert," while he signed his guns, "Drepperd." Gun locks marked, "Drepperd," are found on rifles made by many Lancaster gunsmiths.
The U.S. Census of 1850 gave his age as 63. In 1860 the census called him a master gunsmith and gave his age as 73. In the census, on his signed work and in his estate his name was spelled Drepperd. "Inventory of the goods and chattels which were of John Dreppard, late of the City of Lancaster, deceased .... 10th day of November, Anno Domini 1864 .... household goods bequeathed to Jno. Dreppard, $106. The Gunsmith's tools, ditto, to do, $50 ...."
John Dreppert, Jr. (1818- ). gunsmith. John Dreppert, Jr. was first taxed in 1833 as a freeman laborer. In 1837 he was first taxed as a freeman gunsmith. In 1841 he was taxed as an inmate gunsmith. In 1852 he was taxed as a smith. The U.S. Census of 1850 showed John Drepperd, age 34, gunsmith, in Lancaster city; and the 1860 census showed John Drepperd, gunsmith, aged 42 years, working in the southwest ward of Lancaster city. In 1837 John was taxed as a freeman gunsmith. He was active through 1875. His shop was located at 15 Water St., Lancaster city. [tax; Boyd's Dirs., 1855, 1857, 1861, 1873-74. His name was given on tax and census records as Drepperd. We may note that there was a third John Dreppert, son of Jacob, a rope¬maker, taxed from 1834 through 1852, usually as a laborer.
Michael Drepperd (1818- ). gunsmith. W. King St., Lan¬caster city. [U.S. Censuses of 1860 and 1870].
William Dreppert (1816- ). gunsmith. William Dreppert was first taxed in Lancaster city in 1837 as an inmate smith. He was taxed as a smith through 1852.