I don't imagine a two-barrel set Ithaca Crass Model would be any more or less common than a two-barrel Parker Bros., Remington Arms Co., Hunter Arms Co., L.C. Smith, Lefever Arms Co. or Baker Gun Co. double would have been in 1891. I doubt the short set started life at 21 3/4 inch length. Quite possibly it would have been the original set that got damaged and cut back and a second set was added. All pure speculation.