Yes, Chevy used a limited number of HydraMatic transmissions in pickups. I think they started doing that a year or two after GMC did. There are a couple of distinctive differences in the Hydro that identifies it, such as a rectangular sheet metal housing on the side of the case where the shift lever and throttle linkage fits. That's in addition to the regular sump pan on the bottom. There's also only about half of the fluid coupling covered by the bellhousing, making room for adapter rings to fit various engines, not all of them GM. Lincoln, Nash, and a few others also bought the transmission for use in their vehicles.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!