Yours looks like the 150 or 250 yard model . N Bpth of these were made from 1933 to 1941. The first models had wood knobs. yours is probably a 1938 to 41 model with the plastic (Bakelite) knob. While great old classics, they have nominal value. Usually in the $15 to $25 range. hope this helps
I have the exact side plates on my Seaford. The foot is stamped "250 YDS". The spool width is 1 7/8 inches. Side plates are by Penn and black in color. I do not think these are rare or valuable but they are historic and interesting.
The only difference between your Seaford and mine is the handle knob. Mine is the plastic bell shaped handle. The clicker button on mine is the waffle type.
Here is one with the wooden knob and the waffle type clicker button. No yard stamp on the foot. It is in the box. The sad thing is the lable is missing.