Honda-SOHC

I have a set of CB 650 forks, ( I think) which require replacement stanchions. My originals measure 585mm total length. From the bottom of tube it measures 55mm to the groove. I have spoken to a guy via eBay and the stanchions he has fore sale measure the same total length, but the groove measures 65mm from the bottom. My question is fitting these replacement would it affect the damping, or am I just being paranoid ? Cheers