I disassembled and measure the ejector rods and center pins from two of my Model 53 revolvers.
The ejector rods measured 2.690 inches and 2.697 inches. The center pins measured 3.896 inches and 3.905 inches.
Since the Model 53 is built on a Model 19 frame and uses the same cylinder length, I believe that Randy is correct. That is to say, the ejector rod and center pin would be the same length in a Model 53 and a Model 19.
I didn't have a Model 17 to take apart and measure so I can't tell you what length the parts are in that gun.