Nope. Old Key West originally opened in 1992 (or was it late 1991), and its contracts were based upon a 50 year ownership period, expiring on 1/31/2042.
When DVC started selling BWV, BCV, etc., they maintained the 2042 end date.
It wasn't until SSR went on sale that its contracts ran through 2054.
"Fifty Years" of ownership is not stated in any of the purchase agreements. What is stated is an end date of 2042 or 2054.