Follow up:
Broke it down and most indicators are that it appears legit and manufactured on 09/02/2011. Box, box contents (mic stand adapter, paperwork, sticker, warranty, velcro cord strap, mic bag from China), machined lip, black windscreen/gray cartridge screen, no CAUTION sticker, 1-2-3-Shure on XLR pins, silicone packed, yellow/green wiring, etc.. The only thing that I did not check was weight (.298 kg) and resistance (300 ohm).
The only concerns that I saw:
~the BestBuy58 circuit board inspector stamp was painted white, like the DC"+" sign. The borrowed 58 has "Mexico" printed in red lettering on the circuit board.
~the BestBuy58 SM58 logo around the neck is painted with a thinner, cleaner "SM58-lettering" than the one that I have borrowed.
~the borrowed 58 has three holes (two drilled [one w/ screw, other hole open] and one XLR clip hole). The BestBuy58 has two holes; one drilled (w/ screw) and one XLR clip hole.
In an A/B test with four different pres, the borrowed 58 is slightly hotter than the new BestBuy58.
Conclusion: Sounds good, smooth, and displays the typical proximity effect. Compared to the borrowed 58, I like the sound as it is not as hot. I may have borrowed a cloned 58, or I have two really GOOD fakes.
D