First off, I agree the pictures are in poor shape. Secondly, why are the ones in a sand (Apperas to be sand?) plastic box? Thirdly, I can see that they appear to be made of some sort of steel or even sheetmetal from the dimple going inward on the bottom. But...then again it could just be plastic? Forthly, I thought the Mexican Army was now using a version of our M67 and has been since Vietnam? Last but not least, what is a sud America? I apologize for the insights and educated guesses that I am using but, I, and like the others here prefer a little more something to chew on before making and educated guess? Hopefully, you can or are able to get more pictures on the subject or at the very least give us an idea as to what the writing is on the grenade?