Duquesne Light's mercury vapor streetlights usually had glass refractors in them since the plastic ones always browned out, there were some GE M-250R1's on Rich Hill Rd in Indiana Township, PA that had plastic refractors but they were replaced with drop refractors several years ago.
NGrid will only use glass for a replacement refractor on 250W or higher lights. 50, 100, and 175W lights get formed palstics lenses as repalcements even if the damaged lens is glass. I've seen them use FP lenses on 250W M-250R2s as well.
West Penn Power uses polycarbonate lenses with their newer 100 watt HPS and 175 watt MV streetlights. Their 200-400 watt HPS and 250-1000 watt MV streetlights use glass refractors.
Grid here had a few of these fixtures left but they are on upsweep arms.