To correct an erroneous post, the Mark I Safeties are absolutely NOT
impossible to find. Here's four of 'em that still exist, and I'm sure there are many, many more out there.
The above safeties are quite different
because of the top hook for the Mark I bolt, than the Volquartsen extended safety that's made and designated
quite clearly for the Ruger Mark II & III. It appears that's not very well understood by some around here. Volquartsen does NOT make an extended safety for the Ruger Mark I.
Apparently getting things across in these forums to help, rather than confuse members, is no longer a worthwhile endeavor?
And, a small tapped hole in the thumb button on the original Mark I safety to add an extension will NOT denigrate the value of the pistol.