One of them has 26 3 FP Caldwell stamped on it. The aluminum part is 27 and an 1/8 long.
Paul from SWISCO responded:
September 25, 2017
If the depth of the bottom balance shoe is 1", order the S380-27 side-load balance. If it is 1-3/32" in depth, order S385-27. In either case, the spring weight for your "26 3" will be our 2630.