The part numbers are only found on the paper tags. I have been collecting images of the spring tags as a research project.
I have also created a spring calculator to determine the spring part numbers for a given set of options. The calculators are based on the published options weights. They compute a spring code that can then be matched to a part number.
The 1969 spring calculator is as close as possible without the orignal GM computer tables. The 1970 spring calulator is only off by the new springs that were added for that model year.
You can try them here (scroll to the bottom of the page):
Chevynova.org Project Page
BTW there are a few 1969 Camaro spring calculators there too.
Let me know the results for your car.
Thanks,
Greg