The WWII C-B Rat cans are a silver in colors were the Korean War cans are in the OD color. All the OD C- or B Rat cans I have owned and also shown on here are Korean War dated. I think this is between WWII and Korean like 17thAB wrote (thanks Oz)
According to the QM Historical Studies book, on page 124:
"When in the fall of 1943 a program for applying a corrosion-resistant, camouflage coating to all canned subsitance sent overseas was initiated, arrangements were made...Thereafter C Ration was coated with an olive drab, corrosion resistant lacquer or enamel in accordance with specifications for this type of coating issued by the Quartermaster Corps."
OD coated C Ration cans without dates are definitely in the 1945 and earlier realm. Here is an example with the OD lacquer. Based on the evidence provided by Tom, I am leaning back to my original supposition, that the large labled SUPPER cans are late war, 1945. I'm still debating until we get more concrete evidence, but Tom's comments have me thinking. I'm treating this like an ongoing conversation and were not finished discussing and presenting evidence.