Evening Ian. It's been a while, hasn't it?

I stand corrected - serial number 188XX therefore the DOM would be 1916. To answer your questions:

A: no, the frame has solid bottom.

B: as it appears on both sides

TOBIN ARMS MFG CO LTD.
< MAKERS >
WOODSTOCK,ONT,CANADA

C: the cocking part appears F though it would be helpful to have a comparison.

The firearm locks up tight, is on face but has received a coat of refinishing sometime in it's history. The light tiger striped walnut sold the gun to me.