That's not too tough. You only need the folders where the textures reside. So you go to \SimObjects\Airplanes\CS_airplane model name and look for all the texture folders there. They always come with the prefix texture. and then have a unique name.

If you want to find out, which one got installed last (this should be your added ones), just sort that view after the date for example.
You can also you just backup every texture folder there and later copy them to the new generated folder of 4.5, without overwriting existing files, so only your addon ones will be added.

The second part are the entries in the aircraft.cfg. Just open the file in notepad and backup all the stuff with [fltsim.XX] (where XX is a number).
Unless they fundamentally change something in 4.5 there, you can later add them to new generated cfg file of 4.5.
So it only is a bit of copy and paste work later consisting of the folders and the corresponding entries.