Constantine (who are in Florida now, I think) or ML CONDON 248 Ferris Ave. White Plains, NY 10603 tel: 914-946-4111 should both have it. Since there's quite a range in color I'd recommend actually going in to hand pick something similar to what you have, if you can. (Or to send them a photo or a piece of the damaged section and ask for a match--both are known for outstanding service.)
You may be able to repair the veneer if it has only lifted, by injecting epoxy behind it and pressing it back down, that's a standard veneer repair.
I'd try asking the hatch maker for the right gaskets first, they may be overpriced but the material and shape do count. For generic gasket material, Grainger or McMaster (both online) have large stocks of different sizes and materials. Remember that your old gaskets probably have shrunk a bit--what they measure now, may not be what the correct new ones would measure.
Regular ArmorAll or talc application will help keep gaskets like new for many years.