>>32493493From the pictures in the thread, the writing on the back of the cartridge seems fine, as well as the writing above the part of the chip that communicates with the DS.
As for the red lines, that's likely just the bigger wires showing through. The casing of the cartridge is partly see-through for the IR. There's also a large chip there that has many silver-coloured wires connecting it to the chip, and they're much easier to see through the cart since they're so bunched up, pic related is the insides for at least HGSS and BW. As for why they show up red, I don't know the science behind that, but all of mine do it in certain lights as well.
I wouldn't worry about the creaking either, I bought one new from EB Games years ago and it's been fine.