Probably about a 145 or something, but I don't know precisely.
Shirt weight only tells part of the story (namely the weight of the fabric). Quality is also determined by the type of knit, and the quality of the cotton used. AA's shirts are an unusually low weight, but the fabric is, as far as I know, a fairly high quality (their finishing is a lot more hit and miss however).
A cheap import may have the same shirt weight, but just be a crappy thin shirt. Likewise a heavy weight shirt could still be crappy because it uses a more unfinished cotton - being heavy isn't necessarily a sign of quality.
If you got a high resolution scan of the fabric they're using, you might get some idea of what their quality is like (if you know what to look for) - but really, if you want to know a manufacturer's quality you're going to have to look at an actual sample. Shirt weights give you very little to go on in terms of telling you the quality of a shirt. Shirt weights are more useful for indicating the end-use of the shirt - a thin shirt will be good in warm climates, as an undershirt, etc. whereas a thick shirt is going to be better in cool climates. Often fashion overrides the practicalities of climate, so that also needs to be taken into account.