we are looking to buy a really old towmotor, it has a straight six continental motor in it, i am being told it is a 9 ton, the serial tag has been removed so we have no way to see if we can find parts for this, and osha would not like us to have this with out that tag, does anyone have any ideas if there is a way to get a replacement or is it etched in the frame somewhere? please help eager to buy this truck. thanks