poop, I forgot about a matched set - it was sold as matched, but I don't think it really fits that category.
Noveske Chainsaw-grade FFL lower with matched upper.
Since the Chainsaw grade is a blem or a second, I don't know how that would be "matched," just by definition of being a blem or second. Maybe it was "matched," meaning they fit the blems and seconds together, to ensure operation, and were sold as such.
Sweet pieces, none the less, and I used them to build my Mk12 Mod 0 rifle.