Thanks 32 Magnum. I would post what I got from Numrich but it may be a copyright violation (not the free schematic). It provides that on some models the pin is internal and accessed by removing the tgrigger guard.
The trigger and trigger guard is easily removed bt tapping out a drift pin. Still, while I can see the head of the firing pin screw and I can get the blade of a screwdriver on it, I have been unable to get it to budge but I am being careful not to round off the slot for a common screwdriver blade.
I am going to try penetrting oil and modifying a basic screwdriver shank and then try to remove it. (This would be a cinch if it was on top of the breech.)
The better method might be to remove the hammer, which I attempted, as it impinges on access to the firing pin screw. What I thought is another drift pin, and it is clearly shown in the picture you provided, doesn't want to budge. I wonder if it isn't jusst pressed into place but if the ends are peened over. I have only tried tapping it out with a drift pin and it is possible it comes out with something like a gear puller.
Looking again at your picture, there is a difference between it and mine. They both have a barrel pin with hinged toggle that folds down into a recess cut in the side of the receiver. However, mine is circular while yours is more of a rectangle with rounded corners.
As for getting back to me quickly, don't be silly. I am asking you for help and expect you have other things to do with the holidays.
Thanks.