The 1921 dos pesos has 24g silver - 0.9000 Silver .7717 oz ASW, 39 mm.. Design was used for first issue libertads 1982-1995.Seem fairly common on ebay US.
If I was in US I'd be stocking up on the older libertads and dos pesos. With unlimited funds the gold 20 and 50 pesos are stunning (but beware fake 50 pesos doing the rounds)