Does anyone know what wagons were used on aggregate trains during the 1970s, were PGAs in use then (I believe first variants were built mid 70s)?

Trying to find pictures of aggregate workings on the Southern region 1970-early 1980 (81-82 at a push).

From what I've found so far, which is minimal, MSVs maybe the staple wagons but I'm sure in an old book I saw PGAs behind blue 47s?

Thank you for your help and assitance in advance.