Street light drop refractors were typically made by two OEMs, Holophane and Corning Glass. The make and model is usually marked somewhere on the rim which is only visible from inside the luminaire.
If someone here that has a M-250R2 with a matching refractor, they could check their luminaire and provide that info. Then you can probably contact the manufacturer for more detailed data.
Most streetlighting refractors have a IES type rating on them. The
IES type rating gives the rough distribution pattern of a given refractor. The page I linked is for LED luminaires but the IES types predate LED luminaires and were originally used to classify luminaire refractors.