Did interchangeable parts have to do with mass production?

Eli Whitney is usually given credit, but Honore Blanc was the first to demonstrate firearms assembled from interchangeable parts about 1778. Twenty years later Whitney performed essentially the same demonstration for the US Congress. Neither of these men were able to mass produce their firearms because the parts were still made by skilled craftsmen. In 1814, Eli Terry began production of a wooden clock but his methods were not adaptable to metal machines. Between 1819 and 1826, John Hall constructed specialized machines to cut, form, and mold metal parts for the M1819 Hall rifle at the Harper's Ferry Arsenal and was the first to mass-produce interchangeable parts. At about the same time, Simeon North created the first milling machine that eliminated much of the hand-filing previously required. North also received a contract from the US Congress to provide M1819 Hall rifles and soon parts from a gun produced in Virginia could be used to repair another produced in Connecticut and vice-versa.