The Tin coated pins will help alot but the fit needs to be tighter. When I rebuild other brands I almost alway's need to lightly tap the pins out. If there is any slop when new it wears the pin because it moves up and down in the piston. That is why it is important to change them out once in a while, if it gets too bad it will wear the piston also.
I have been seing Tin coated pins in the new motors also for the last couple months also.

Rex