Savage stamped the model ("F", "G", etc) into the receiver's front metal on some guns, visible only after removing the forend.
Here's a Model 99-EG so stamped:
The circled "H" on the receiver bottom near the lever hinge might be a Lever Boss Code (LBC), which is a manufacturing date code for a rifle's DOM - BUT the LBC's only started in 1949, IIRC.
I misread the OP, thinking the "F" stamp was in the front of the receiver metal, ILO the forend wood & iron.
I don't know what the "Z" stamp in the receiver front metal signifies.
I think I'd need to see a few pics of the rifle, including full-length shots, to comment further.