Have the date codes down. Even the 70 and up 'W' codes. The 'Buildsheet' newsletter with the 69 info went with my last GS. So, how can you ID disc brake vs drum 1969 ralley's? I have a bunch that are 69 (M49) and a couple that are thick-lipped M49's... I would think the 'thick lipped' ones are for discs?? Thanks