Center link question

[Todd68Chevy]

Is there a chart or a thread anywhere that states what center links are the same as others. I have a guy looking for a center link to convert his 1968 C10 with ram assist power steering to a regular power steering box set up. He says it has disc brakes? I assume it must be disc brakes on 68 spindles? I have the following center links:

1. 1967 C20 non- power steering
2. 1968 C10 non- power steering
3. 1969 C10 non- power steering
4. 1971 C10 non- power steering
5. 1972 C10 power steering
6. 1972 C20 power steering

Does anybody know or where I can find out, if one of these will work or what he needs to look for. I think the 1968 C10 one should work but not sure if it will fit the p/s box pitman arm. Thanks for any help.