You've posted here before that some of the LS units for sale on ebay and other places are actually "old" stock units or otherwise out of date, etc., and therefore a bad purchase.Question: How can I tell the date/model of a particular unit? a "friend" has an unused one for sale, says it's only a couple years old. I'm going to look at it later today, but wondering is there a serial number or something I can get off the unit to verify date/model/year or something? How would I do that?TIA