First question: Endlinks do vary per model. For example, the a386 vintage, a384, a385, a277, a386 revival, among others all have ladder bracelets. The a384 and a385 have a flat endlink whereas the a386's endlink is curved. Also the a386 has 19mm lug whereas the a277 has 22mm lugs. So be careful, they are not interchangeable.
Second Question: My opinion is that $1,000 is pricy for what it is. I realize that this may be "market" at the moment given their rarity, as you've cited, but consider this: I was in the market for a GF bracelet for my vintage a386, which go for $1,500 and up... the endlinks are similarly expensive. But in my search, I discovered that Zenith actually manufactures the ladder bracelet for the VINTAGE a386s as well as for the modern revival 386s. It is the exact same bracelet as the old GF ones. It cost me $300 brand new directly from Zenith. And by the way, had I only wanted to buy the end links it would have cost me $40.
So... I would at least inquire with Zenith to see if they have any or could make any for the a277s. That said, the ladder bracelets look killer... especially on the a277s, which are some of the best looking chronos ever made IMO.
