it depends in this case I certainly would like to conduct an interview of the person I am buying the shaft from. If we are similar in swing style and golfing ability then maybe. I'm not familiar with 7D spec sheet order so don't know if mystatic strength stats or lag or a multitude of factors play a key role in shaft.
I'd certainly be more comfy buying my twins 2nd hand shaft than say one made to jack HaMM BBOOOMMMMM specs. Get what I'm saying? If they made a shaft for oompaloompa with 70mph driver swing speed even if it was sold for a bargain I would be wary to buy it bec of my personal specs.
I'm not a believer in 7d second hand shafts. That's fudged up.