New member with another 99 question.

Hello folks..
I am the proud owner of a model 99 in what I consider almost new condition. According to the tacked thread above she was born in 53.
The question I have is..the stamp on the lever boss doesn't start with a letter..it is the number 27...there may be another character after the 7 but I can't make it out.
Does this mean anything significant or is it just a proofing mark?

I think it might be a 52 if it starts with 27.

Whats the serial number range late 600's? 695XXX?

Welcome from Gettysburg Pa

Welcome from Michigan, I was told the two numbers are the inspectors number and then letter that should be the year code mine is a 1951 letter code C ser# 606xxx I hope this helps !!!