goodiewrench - the link you posted shows an early 1919 NRA (pre 1923) that has a much later No 25 hooded sight which shows up for the first time in the 1940 parts catalog.
The gun you reference also has the early rectangular bolt but has the more open ejection port and two screw rear sight - the only differences from the very early ones that I know of.
The 1919 NRA was updated in 1923 with the 'new 23A' bolt. These 1923 versions were also offered in 22 SHORT, not just the early ones. I am still tring to find out what magazine was sent with the guns in 22 SHORT - I have never seen a magazine for one just marked for 22 SHORT.
Riverpines gun should have the early small ejection port with that low a serial number.
Gene