I have never seen one, but, according to the parts manual, Chevrolet offered a Bendix unit for non HD trucks. They list the repair kit as Bendix #377774 and the Chevy #3738755
I only see the Hydrovac offered on the HD trucks.
Power steering is a different issue. According to the parts manual, power steering was not offered on trucks until 1959.
Bob

55 Cameo 396 TH 400 with overdrive
65 Caliente conv
67 BB Caliente conv
67 Mercury 1 Ton
76 GMC 3/4 ton 454ci
84 Buick Turbo Regal