Ok, I came across this plane a couple of years ago. It is marked Sargent very best made, 409. It has a corrugated  bottom. 2 1/2" wide, 10" inches long. I believe this is a one-off

It is setup as a rabbit plane. I can't find this plane anywhere in the Sargent catalogs. It had no blade or chip breaker. The cut outs on the sides look like  they are factory made.

It will ship at 3 1/2 pounds from zip code 01607.