I've found a lot of local variation...
John in New Mexico
>In Tucson, almost everything at Lowes and HD was green douglas fir, with the exception of SPF 2x4's and 2x6's in the shorter lengths. Here in NM, those same chain stores seem to carry mostly hemlock fir, mostly surface dry, with the same SPF studs. Now if I go to a wholesaler in Albuquerque, I get white fir which is a lot like hemlock, though not as strong for construction purposes. At this same wholesaler though, if I buy 2x10's or 2x12's they often have pine from AZ or NM as well, which is really nice wood as construction lumber goes.
So other than the grade stamp, I don't think you'd have any way of knowing what your local borg carries, just depends on whats available to them.
John