The collecting guide* I refer to lists the "6251CLASP Knife & Fork" pattern (6-3/4"; apparently very big knife) in green bone, in the 'Tested' era (pre-1940). Also listed is a 9251 pattern in 'Imitation Pearl', in the same time frame (pre-1940).
There's also a smaller 6252 "Hobo - Knife & Fork Combination" pattern (3-3/4") in green bone, and a 3252 in 'composition ivory'; same config and same time frame.
There's no listing or mention of these patterns anytime past the pre-1940 'Tested' era.
As compared to the current '54HB pattern Hobo, size seems to be the most obvious difference. Looks like the current version is 'in between' the larger and smaller older versions, at 4-1/4" in size (closed).
* = The 'Official Price Guide to Collector Knives', Fourteenth Edition, by C. Houston Price (2004)
David