Ron of Va,
The one your looking for is similar to the one on the top left of page 648. Tang peep sight, maker unknown. This sight is similar to the Marbles tang peep and what you will be looking for. The distance from hole to hole will be of help locating. You might see if you can locate some fist year model 39's in a museum that have the sight still on and get an idea from there.
Joe
It is odd that the sight pictured on page 648 that says it was for the Model 39, and illustrates a tang sight with very close hole spacing. I think my hole mounting “spread” is greater that what is shown.
There was a response to my post over at RimFireCentral, which illustrates a group of tang sights that appear to have the same mounting spread, and according to the poster, my gun could have even come with a Lyman with an “H” stamped on the bottom.
http://www.rimfirecentral.com/forums/showthread.php?t=308317I think the search will get tricky. I really do want a tang sight that would be original to the period. I don’t have any firearms museums around here, but I think I will eventually stumble across the correct tang sight at a gun show, or on Gunbroker, etc. .
My son has a son, so you can guess where this Marlin 39A is going.
I really do appreciate all the knowledgeable people who have given advice. Good guys all.