Piasecki H-21 Workhorse

This is a Piasecki H-21 Workhorse. I can't get confirmation on its identity but it is probably 53-4329/N6974. It was operated by the USAF until 1987, when it was given to the Museum of Flight. It was on display for a while, and was likely in the restoration center because it had been out in the open for too long!