Been out of touch for a while but got an email this item was brought up again so I thought I better respond.
This sheet is definitely the CHASSIS Broadcast sheet and not the BODY broadcast sheet. I haven't been able to get to the car or the sheet lately (like I said, it's really stashed away) or I would get a better photo and breakdown of the details to you guys (be patient). The code at the bottom is 5712 followed by two letters, A and one I cannot see clearly in my current photo. I was under the impression that this would be the same code for the interior (in this case 712, blk custom) that would be shown on the window sticker, etc.(i.e. 5712AA) The two letters apply to the ECL codes that follow the option codes.
After checking the CHASSIS sheets for some of my other 69 LA built Camaros, I finally noticed that section 148 on line #1 says "EXP PREP" which might be a good indicator for an EXPORT PREPARATION vehicle? Unfortunately, that portion of the Z/28 sheet did not survive. I'm agreeing that it was most likely not an export vehicle due to the LA build instead of Norwood, but you always hope to find some exception to the rule........ (i.e., needle in the haystack).
Thanks for your help and I'll try to get more info sometime in the near future.... Charlie