Subframe Stamping and Inspection Mark

[Camarocards]

I'm into the subframe part of my 68 SS restoration and found the stamped numbers shown in the image on the drivers side of the subframe. The car is a 01D build so could the upside down "10" indicate that the subframe was built in October?

Also, I found what appears to be a yellow inspection mark on the front crossrail of the subframe. Has anyone else seen an inspection mark there?

Thanks,

Bob