I think it is going to be difficult to determine the era these items come from based on the colour. I have checked my manuals and most describe the 1/2 lb charge as yellow in colour.
TM 9-1946 Demolition Materials November 1955 - The 1/2 pound block is in a yellow container 1 7/8 inches square and 3 3/4 inches long. One end of the block contains a threaded cap well 2 1/8 inches deep to receive a priming adapter or a coupling base.
FM 5-25 Explosives and Demolitions May 1967 - Case - Cardboard with metal ends; threaded cap well. Colour 1/2lb yellow or OD. Size 1/2lb 3 3/4 x 1 3/4 x 1 3/4 in.
FM 5-25 Explosives and Demolitions March 1986 - Size 1 3/4 x 1 3/4 x 3 3/4 in. The 1/4 pound block is issued in a cylindrical waterproof olive drab cardboard container. The 1/2 pound and 1 pound blocks are issued in similar rectangular containers. All of the three charges have metal ends with a threaded cap well in one end. (I assume these would all be OD as the colour for the 1/2 and 1 pound is not stated)
NAVWEPS OP 2212 1 February 1962 - The charge consists of a 1/2 pound block of compressed TNT enclosed in a yellow water resistant fiberboard container having metal end closures. An activator well, which is not threaded, extends about 2 7/8 inches into one end of the block
There are some physical differences that may help narrow down when these charges were produced.