Looking at the Swiggarts illustrated manual, 6s seems to have only one style (in 1952) so I would say any set from another Elgin 6s should be fine.
You could try http://www.elginwatchparts.com for your grade, but I just checked for a couple of mine and all it says is 16s.
I do mainly 18s and 16s Elgin, and the hands are interchangeable within the sizes for different grades. Mind you, some of the hands need tightening to deal with old arbors, or from being put on an off many times over the years.
Peter in Oz