Craft, Alfonso has
a couple of downloadable PDFs on his site in which ALL the specific missions of the shuttle are shown, what the orbiter looked like during that specific mission and also the external tank and boosters. In that document you can find all the information you need about when which modification happend on each of the orbiters.
(Look for Space Shuttle External Markings)
Secondly, in the end it is
your shuttle. No one will notice you might not have used the correct configuration of that mission.
Good luck with your build!