Hi Glenn,
Using nickel silver pins is not unusual on slipjoints, but usually to get the bolsters and pins to match use the same or virtually the same material for your pivot pin and your bolsters...nickel silver for both.
410 and 416 stainless are the same color and close enough in "texture" that you can use 416 pins in 410 bolsters or 416 pins and 416 bolsters..( I haven't found 410 pin material but it isn't required in 410 or 416 bolsters.)
The only reason for 410 liners and 410 or 416 bolsters is that if you are silver-soldering thicker bolster to thinner liner material, 410 comes in down to really thin sheet and up to thicker sheet and 416 doesn't come in much less thick than 1/8"
Either nickel silver or 416 pin material both come in 1/16" and 3/32" diameter, and larger.
416 is a bit harder to make "disappear" when peening in 410 or 416 than nickel silver pins in nickel silver bolsters, but not that much more so.
on the folder in the picture you posted, if the bolsters are either 410 or 416, I'd drill and re-pin with 416 pins....polish the face on the hammer you peen with, use .001 or .002" thick ssShim material and take your time to peen it. then peen a little more...once you get it where you think you are OK, then take out the shims see how the blade walks and talks....if too tight, I use a brass "wedge" ground on the end of a brass rod to open it up a bit...or if loose don't tap it much to tighten the pivot.
Good Luck. You obviously have the skill and experience to get it done. It is just a matter of getting used to 416 pin material rather than nickel silver.....
I hope this helps. It wasn't long ago when I went on a frantic search for 410 pins because I wanted to try using 410 silver soldered to 410 liners...and figured I had to have 410 with 410.....Mete, who often posts on these forums and just happens to be a very sharing metalurgist said the color is the same...the texture is slightly different so it may sand and espc polish a bit differently. And at the same time, my one of my very favorite slipjoint makers in the world said 416 in 410 is fine...he hand finishes with backed "sandpaper".
Mt experience is that both are absolutely correct. 410 and 416 together do wear differently if buffed much...the pin will "re-appear"....so hand finishing with a backed paper or really fine (9 micron is polished finish) belts...then a light hand rubbed finish and very light polish with chrome rouge....emphasis light....on felt or hard stitched wheel....not much though.....
I chatter on, sorry,
