There is no "19" on the frame but since the sideplate does not match anything else on the gun that is not surprising. There are no numbers in that area of the frame. Only the two marks descrbed above.
All the parts show a consistant amount of wear so all these mismatched parts are about the same age if looks are an indication. <img src="graemlins/yltype.gif" border="0" alt="[typing]" />