Rear Axle Marking - Factory or??

[Hans L]

Noticed this blob on the rear axle housing - factory or someone else's graffitii?   '69 Z28;  04B LA Built car.   BV 0403G1 Axle code....

[NoYenko]

Hans, I didn't find any marks on the front of my diff. But I did find an orange spot on the back next to the cover and purple paint inside the yoke under all the grease. I think maybe to verify pinion nut torque.?? Check those areas also.