help with dataplate info please

[cmp_uc_guy]

The first pictures I am going to post are the number on the door (which looks like "Z" over "51-300") sound farmiliar to anyone?

and what looks like the tac marking thats leached through the paint below the passengers window.

Also the bridge class circle (which looks like it was done then painted over then done again slightly offset from the original.

The picture thats there now shows all but from far away.

Give me a few hours till I get off work to post the rest.

Rob