Ask Gary at Textile_Specialist for his 500d closest in shade to the 1000d Sandstone?
I mean the Army's WWII spec for OD#3 had a range from golden to pea green, the current Army spec for Tan499, I've noticed some variance in the shade, too.
Lot to lot, mfg to mfg, yard to yard on the same roll even (whole reason cutting tags are used in industrial sewing processes)