Actually no but that would be a logical description. the lifter on the left is what is commonly called a milk bottle lifter. Completely flat sides, looks like a milk bottle or milk can. The lifter on the right is a solid lifter for the 56-62 261 truck motors. I have seen the lifter you have once in a while. Its aftermarket (I think, but only because I have never pulled one from any of the motors I have ever taken apart, only seen them as sealed power lifters) and I have never used that style myself so I cant opine on whether you should use it or not. I never liked the design so I never used it. I always used the version that mimicked the hydraulic lifter design when I was retrofitting solid lifters into a hydraulic lifter motor.
