I'm wondering if the metal uprights that hold the glass, between the glass sheets (it's plexi, isn't it???), are held onto the boards via a turnbuckle-- I'm picturing a cable running from the boards-top to the top of the metal upright, with the turnbuckle to tighten to the correct tolerance for specs/glass stability. That whole assembly might be referred to as the turnbuckle, and it might be that the checks referred to are the ones where the glass ends at the player bench. If that is the case, there would be no exposed hardware-- it would be in the metal sleeve-- but the tensioned metal sleeve would be not-so-fun to be run into/wrapped around.

Our pop-up camper has a turnbuckle at each corner as part of the latching system for the pop-top, so it's easy to picture the above-- but is it correct?

~Susan