looks like Mystery Misery Meat to me
Before the MRE for the military, there was the “C” ration. If you opened up the can of spam that was in the box....it’d look kinda like this. Course, the spam can had about 250 calories. This slice of “ham”? Maybe 40 calories max.
To me, it brings back memories of some of the messhall dishes at Camp Pendleton in the 1960’s..........