I put on the old hiking boots and walk the entire swap meet at least once. Perhaps there is not as much NOS sheet metal as there has been but if you look, you will find.
It amazes me how much you can find if you dig. The best digging is usually in the non Model A booths. That is, if you are looking for NOS or other items to swap/share with guys doing fine point restorations.
If you are looking to keep your Model A in shape for tours, shows or daily use, or are elbow deep into a restoration, the Model A booths are great because you will find what you need and someone to talk about A's.
Being a very early 28 guy (I'm so early that I'm really a '27 guy) it is tough to find those needles in the Hershey haystack. However, the perverbial needles can be found. For example, I bought the on-off-dim switch that I will use on A495 at Hershey. It was laying on the ground with some, slight surface rust. I picked it up and saw 500 on it. Well I walked up to the vendor and asked how much he'd take for it he said $5. My hand was shaking when I gave him the money. If you know what you are looking for there are still parts and deals to be had.
Remember, if you are in a space and are interested in something keep it in your hand. If you set it down it might be gone in a blink. Also, most guys will accept an offer of 10% or more off their price.
Man, just talking about Hershey I get pumped up. Wow, just a month away.