In 1950, chevrolet introduced the powerglide transmission. The at887 lifter was never used in a power glide motor. Solid lifter cam only. Early 887 lifters were chilled iron, later, maybe in the 90s, 887 started arriving made from a material that would be compatible with steel or cast cams.
As for reconditioning of the lifters, Delta Cams or Rocker Arms Unlimited, either can resurface the lifters.
http://www.rockerarms.com/pages/lifters.htmlhttps://deltacam.com/services/