Factory leaf springs

[DONCZ28]

Are there any markings, or part numbers stamped on factory leaf springs?  Found a pair for my 69Z that look correct butcan't find any markings.

[bertfam]

http://www.camaros.org/forum/index.php?topic=15451.0;all

Ed

[DONCZ28]

Thank's,  my one spring has GMU raised twice on the same leaf only. The second  spring has no GMU , but all the leaves on both look to be of the same age.