Cylinder marked "2"

[mmande]

Hey Guys;
I bought a 5" 27-2 that dates to 1978 this weekend and I was cleaning it up today and noticed that the cylinder was marked with a number 2 on the breech end. I had never noticed this before. I know that the Highway Patrolmans were marked with an H and I believe that was so the bluing department would know what finish was required. Is that the same reason this one is marked with a number 2?
Just curious;
Mike

[Oldengineer]

I have noticed the same and await an informed response. Thanks for asking.