That may be the case.. but having had a horse about this age with OCD I would get xrays. It is not fun to breed a mare and get a nice foal that ends up being put down just as he enters training because he has OCD lesions. Nicest gelding in many many ways.. and just a joy (they always are, aren't they?)
Get a diagnosis of that hock. A thoroughpin was not treated back in the day (back in MY day LOL) and was considered a blemish.
I would like you to be right Foxhunter. My suggestion is to make sure as there is no point in the heart break or the money trail OCD can take you down!.