Letters in Fender extensions

[sixt9x33rs]

Can someone tell me what this "GR" means inside my fender extensions. It does not mean Green. My car is Olympic Gold and I spoke to another RS Z/28 owner whose car was built one week later than mine and he too hat this written inside his fender extension. His car was Phantom Green though. Perhaps this like he "XO" on the inside of the fender helps tell the line worker something about the assemble of the car? If some can tell me what this means that would be great.

Thanks

[sd1968z28]

probably some code written by a salvage yard at one time.  looks way to new to be original marking.

[sixt9x33rs]

probably some code written by a salvage yard at one time.  looks way to new to be original marking.

No that is not it.  The reason the markings look "new" are because the surface rust has been removed. This is the second time this "GR" has been found on 03 RS cars. Just dont know why??

[william]

Body broadcast sheets are full of two-letter codes. Box 103 is fender piercing: YA has been seen on both COPOs and Z/28s. Since neither received engine ID it may only indicate the "Camaro" script on the side. I have a copy of a Z/28-RS sheet and the code is YB.

More interesting is box 104 "emb". For Z/28 the code is G. The box is blank on COPOs. 

[sixt9x33rs]

Body broadcast sheets are full of two-letter codes. Box 103 is fender piercing: YA has been seen on both COPOs and Z/28s. Since neither received engine ID it may only indicate the "Camaro" script on the side. I have a copy of a Z/28-RS sheet and the code is YB.

More interesting is box 104 "emb". For Z/28 the code is G. The box is blank on COPOs. 

Wonder if the "R" beside the "G" in the fender extension is for RS cars?

I posted a picture of the "XO" code inside my fenders and John Z mentioned that these codes were used for piercing of the fenders. I guess for RS cars since my car is a RS Z. Have you seen "XO" before? There was another 69 RS car in the paint shop the same time my car was there and it too had the "XO" markings inside the fenders. However this other car was not a Z/28.

Thanks