It depends on the vendor. Some quote the fabric weight before silicone treatment and some quote it afterward. Sometimes they tell you what the quoted weight is based upon and some don't.
Before Dutch's Argon came out, I would have said that any advertised 1.1 silnylon is the weight of the raw fabric and it will weigh closer to 1.4 after impregnation. ( Argon weighs 1.06 oz/sy including the silicone).
Read the fine print and email the vendor for confirmation if in doubt.