Shipping dates in the 1930s can vary, as the Depression slowed business and guns could sit for some time. So extrapolating is not as certain as for other periods, but the serial puts it definitely into the later 1930s, likely 1935/36, but it could have shipped later.

PS: Closest to your 659919 I’ve been able to find is 658121, shipped in Jan. 1937. But I think the sideplate logo changed in 1936 to the right side, so yours was at least made, if not shipped, before that.