Mike,
Those seats look terrific. In fact, almost too good.
Remember these are stadium seats. Most never saw any kind of preparation, or restoration. They got painted. Every few years. Period.
In the case of the Yankee Stadium seats, some (the straight back and seats) went into the Stadium in 1923.
The curved back and seats, were installed sometime in the 1940's when they pulled the folding chairs out of the box seat areas.
If you want to make them look like they did, get some of that Yankee Stadium blue, from Sherwin Williams and slather it on!
(But, like David said, you did do a terrific job of restoring them.)