The one on the left is strictly a rigid (probably work on IMC) hickey. You don't bend rigid in one shot with these fellas but "walk" it up the conduit, the spring made it easier to move up that way... you mean they don't still make them??????? geez, I'm heading to e-bay
The other old one will work on emt, but it looks as if it were made prior to that era, same thing applies about the movable front shoe in case you wanna make a 2 or 3 shot bend.
Early 70's, y'all check your ancient code books, EMT is ONLY allowed in up to 2". None of us used that 'junque' in those days, it just looked sloppy, so the one shots like your blue handled benders were kinda rare.