Hi Mowalker,
Our previous Keystone had the same rear kitchen/living area as your Springdale -- TV behind the slide-out when retracted. Ours didn't have a pin, but instead a lever to release the locking mechanism. Very inconspicuous, only about 6-8" long, slender, black tubular like the rest of the metal - ours was on the right side. Push the lever up/down to lock/unlock... when released, the TV pulled straight forward, and would then pivot as expected. When locked, it would only swivel about two inches or so. No doubt a 'safety device' for TV's behind the slide-out when retracted.
If we keep tossing out ideas, hopefully you'll find an answer!
Terri, the Chevy co-pilot