bsa a7 piston part number , not in parts list

[oceanobsession]

Just removed the head on my bsa a7 , thought the engine was seized , not run since 1969 , but its ok dont seem to be a large lip
on the barrel , piston part number is 67-1423 , cant see this in the parts list , would this be an oversize piston , phil,

[JulianS]

67 1423 is the number for the bare piston, standard size.

The book shows 67 1422 which is the  number for the complete piston with rings pin circlips.

[oceanobsession]

Thanks julian , for your help , phil.