Bearings will be the same unless it has been rebuilt before or is a re-manufactured engine. Don't purchase bearings until you can pull some of the crankshaft and piston rod journal bearings off and read if they are Standard, .010", .020", etc. They will be stamped on the underside if undersized. A used engine is anybody's guess unless you know the history of the engine from the PO.
As Matt has pointed out, there are differences in the engine gasketing and the engine code will tell you what year for sure. 1970-1980 engines for example had single barrel carbs and no intake heaters and had gaskets for both intake and exhaust. 1981-1985 engines have intake manifold heaters, 2 barrel carbs, 7/16" head bolts and no exhaust manifold gasket. 1986-1990 are the same as 1981-1985 with the exception of 1/2" head bolts and I believe, a different gasket for the valve cover.
Engine code location: