On the 1909, I'll leave the patina. It just wouldn't look right to me if the bolt and receiver were brightly shining while the rest of the rifle dooks like it does. Later this year I'll let it lay out in the sun to get some oil out of the stock.
There is just something about the combination of the Lange sight, the pear shaped bolt handle, and the "MAUSER ORIGINAL" marking that makes it stand out from all other Mausers.
The rear sight is numbered to match the receiver. I don't know anything about square dots between numbers and I don't remember any on my M1891 Peruvian.
I'll probably never shoot it. I have more guns I have not shot than guns I have shot, although I have ammo in all the calibers of my guns. What I do need to do is sight in my night vision scope on my PSL (in case of zombies). The regular scope is long since sighted in on the PSL and on my PU sniper.
Regards,
Bill