i only know about the numbers for the first year 1175 cars came with the sunroof option that's 3.5% of the 72 production: 33,728 cars did you know you couldnt order the sunroof option with manual windows? edit: found some info about the sunroof for the 73 riviera:
there is an official 1972 buick sunroof service manual this one is for sale on ebay for only $14.50: https://www.ebay.com/itm/1972-BUICK...OP-REPAIR-MANUAL-ORIGINAL-GUIDE-/303310683064
And in 1973 117 or .3% Manual Sun Roof 1091 or 3.2% Electric Sun Roof Total 34080 and 1234 Stage 1 and 3933 GS
So since we are on this subject. I almost bought a fully loaded dark blue 72 Riviera GS that had the factory sunroof. White interior car. Anyone know of that car here?