Two laws are conflicting.
While "open carry" is legal in the State Of PA.
The Pittsburgh Police are required to check out all "Man With A Gun" calls.
So technically...you may "open carry" in Pittsburgh but, if some "concerned citizen" drops a dime on you because your legal firearm is visible/open then you are likely going to be stopped and questioned by the Pittsburgh LEOs.
I just always carry concealed because that's the I like to carry anyway.