Can anyone tell me why older reproduction deck lids are low in the center and high in the corners and if there is a way to fix this or do you just have to buy a new deck lid thanks Tommy

Just age i guess. I had a new one installed, as the old one was too rusty to save.

I posted an answer to this problem before and it is common for all deck lids, aftermarket and original GM. Just stick a 2 X 4 in the middle of the trunk jamb and pull the lid down on it slowly but firmly until it sits higher in the middle. You can also slip a 2 X 2 in the "U" shape of the hinge and open the lid upwards to bring the corners down. It works great.