Larsen is a Class III in Wa and his mags are from D&H Industries - he just had his name put on them - Teflon Coated and are good to go.
USGI means US gov't issue and covers lots of brands - basically any that are built to the mil spec. can be considered usgi. In this case the D&H is not since they hard coat anodize them and then use a Teflon coating where the mil-spec calls for a dry-film finish. Here is a link to the brand rankings of magazines
. Good reading before you buy any mags... In this case Larsen's would fall into group 2.