I just called the U.S. Mint this morning to ask this very question to settle this for my own "need to know" for sure one way or the other.
And although I also believe it is certainly a "P" mint proof held back in reserve from the total minted in Philly, the "not knowing for sure" once somebody put forth this comment has been eating my brain alive.....so I called.
Well.....the lady at the Mint was absolutely sure it was a "P" mint, but could only have the same information as we do......which is trying really really hard to look at the picture of the Set ! .....

So.....I still don't know "for sure"...

....
but I'm sure enough, that I'm not going to give it another thought anymore.
Other than a fellow CCF members comment.....there's no tangible evidence that has been put forth saying "this is" an "S" mint Lincoln Silver Dollar in the Set......so.....lacking that......no more mental energy will be wasted on being curious about it from me !
It just
ISN'T a San Fran production Lincoln Dollar......would've been nice....but it ain't.....

...and, IMHO, we'll all find this to be the case once it's in our grubby little hands sometime after 11/13/09 ! ....

Edited by eaglefoot
10/19/2009 11:48 am