1919.
If the piece is a : "Colt Model 1903, hammerless, 32acp" Then the serial # 221838 was produced in the year 1916. This is according to "Colt's dates of manufacture" by R.L. Wilson.
A Colt 1903 hammerless .32 with that serial number was made in 1919.
1903
Found a Colt 1903 hammerless with that serial number made in 1917.
The 1903 Colt Hammerless .32 with serial # 137295 was manufactured in 1912. about 1913
Your colt model 1903 hammerless 32cal was made in 1916.
Your 1903 colt hammerless 32. was made by colt in 1920.
The Colt 1903 32 ACP with serial number 35xxx was made in 1944.
1934 for the Colt 1903 hammerless .32.
The Colt 1903 hammerless .32 serial # 291320 was produced in year 1919. (290000-327999) about 1912
Is this a Colt 1903 Hammerless .32? If so, according to the information found at http://www.proofhouse.com/colt/index.html it appears your Colt 1903 was manufactured in 1920.