Greg, my JR2 is a 1969 version, an the RS is a 1977 version. both have the ram linkage like that pictured in your first picture, the JR. they have cast on one side "RCBS" and "JR2" and "RS" on the other. if they didn't have the model number cast into them, they would be almost identical. the opening size is the same as well. the only real difference is the handle grip. the JR2 has simple plain black one and the RS has ribbed and fingered green one like a bicycle grip. the 1969 JR2 was given to me by my father many years ago. he bought it brand new. the 1977 RS i bought at a garage sale in the late 1980's best i remember with a bunch of other stuff. so going by your pictures and descriptions, then neither of mine have the compound linkage. thank you for providing the link. i'll save it to my favorites.