.32-20 number 127612 shipped in May 1927.
128840 shipped on June 27, 1925, BUT that one is a target model chambered for the .32 Long cartridge (yes, it sometimes happened).
.32-20, a 6" target model, number 130146 shipped on September 22, 1926.
In any case, yours at 128159 probably left the factory in that time frame (1925-1927). They did not ship in serial order.