Don't know how much this will help:
From the U. S. Army Tank-automotive and Armaments Command.
Looks like the MIL Spec has been changed to a performance spec.
MIL-L-2104 REWRITTEN AS MIL-PRF-2104
MIL-PRF-2104 Lubricating Oil, Internal Combustion Engine, Combat/Tactical Service.
Further research shows that it is available in different weights and amounts.
MIL-PRF-2104 Lube Oil, I-C Engine, Combat/Tactical Service [OE/HDO-]
9150-00-189-6727 OE/HDO-10 1 qt can
9150-01-177-3988 OE/HDO-10 1 qt bottle
9150-00-186-6668 OE/HDO-10 5 gal can
9150-00-191-2772 OE/HDO-10 55 gal drum
9150-00-186-6681 OE/HDO-30 1 qt can
* 9150-01-433-7988 OE/HDO-30 1 qt can
9150-01-178-4726 OE/HDO-30 1 qt bottle
* 9150-01-433-7974 OE/HDO-30 1 qt bottle
9150-00-188-9858 OE/HDO-30 5 gal can
* 9150-01-433-7986 OE/HDO-30 5 gal can
9150-00-189-6729 OE/HDO-30 55 gal drum
* 9150-01-433-7978 OE/HDO-30 55 gal drum
9150-00-188-9862 OE/HDO-40 55 gal drum
* 9150-01-433-7970 OE/HDO-40 55 gal drum
9150-01-152-4117 OE/HDO-15/40 1 qt can
* 9150-01-422-9346 OE/HDO-15/40 1 qt can
9150-01-178-4725 OE/HDO-15/40 1 qt bottle
* 9150-01-421-1427 OE/HDO-15/40 1 qt bottle
9150-01-152-4118 OE/HDO-15/40 5 gal can
* 9150-01-421-1424 OE/HDO-15/40 5 gal can
9150-01-152-4119 OE/HDO-15/40 55 gal drum
* 9150-01-421-1432 OE/HDO-15/40 55 gal drum
(Note: * designation identifies re-refined products)