Does a 1989 Chevy truck engine have roller or hydraulic camshaft?

1989 Chevy trucks used a variety of engines, and the camshaft type varied depending on the engine. Some had hydraulic flat tappet camshafts (not roller), while others (less common in that year) may have had hydraulic roller camshafts. You need to specify the engine (e.g., 305 small-block, 350 small-block, 454 big-block, etc.) to get a definitive answer.