2, are you saying Lowe's was able to order siding to match yours, even though it was not a brand they carry?  Or, just that they were able to match the color with a brand that they do carry?
Looking at their web site, it looks like they carry 5 brands, plus something called "unbranded".  But they don't list "Alside" which is my brand.  Perhaps I'm making too big a deal out of this, maybe siding is siding...  I know even less about siding than I do about treated wood.
I do know this, if I can't get pretty close to an exact match, it's going to bug me.  A lot.