matching tag to chassis explained with pictures

[HK1837]

So how does this stamping look to you ?

Figure its been re stamped then if what you say is correct across the board.

Did it make any difference what plant they came from?

With stamping sometimes it does get hard to tell. These were stamped by a single air operated device that carried the stamps. Those witness marks above the stamps do happen, not sure how the droopy 0 could occur though. I have seen some ugly stamping though, on both engines and chassis.