[quote="Garlic Pete"]That is most likely the master pin. The updated master pins are an interference fit without plugs or splits. You other picture is one of the several variants of master pins which were contemporary to the machine.
Those updated master pins do have dimples in the end to allow identification as you are doing now.
The way to make sure that is the master pin would be to look in between the track pads with it on the sprocket or idler, as you have it in your pictures. The master link will have a shorter bushing which terminates flush with the inner track link. They'll have a spacer ring which fills the recess in the outer track link. You should be able to look in the crack with a good light, or perhaps fish in there with a thin piece of steel, like a steel ruler, to establish that this link doesn't have a conventional bushing.
I'd hate to have you drive that pin out and find that this isn't the master link. Any link other than a master link can't be separated by driving out the pin since the bushings on all other links extend out from the inner link into the outer link.
If this is the only pin with a dimple and all other pins in that track are normal flat faces, it is almost certainly the master pin, but inspection of the crack between the inner and outer link or rail surfaces will tell you for sure.
Pete.[/quote]
Success. It was the correct pin. I made A driver and it took about A dozen good hits with the sledge. Thanks[attachment=43800]0728171019.jpg[/attachment]