other than marketing, what makes it a sporter?
just marketing
these rifles were originally imported as "sporting rifles" , ie: target shooting and hunting markets
To the OP , 2007 and older rifles aren't worth more and the heel stamp is nothing more than nostalgia to a collector of these rifles.
Those of us who build these rifles or have in the past..... we seek the 2007 and older rifles simply for their receivers not because rifles 2007 and older were somehow built better. Chinese quality control has been crappy the M14s/M305 whole existence , norinco or polytech….. it's all the same, same, same. BUT it is widely accepted by many knowledged and experienced M14 smiths who have taken the gauges, tools and heat treat testing to those receivers and they are deemed to be "on par" with their USGI counterparts. The same can not be said for anything imported after 2009.
After 2007 we were warned by John at marstar that the Chinese assembly lines were nearing the bottom of the decent parts bins.
It's my belief from seeing dozens of not a couple hundred rifles across my bench after 2007 that I was seeing that Jon was right..... and I made my exit from working on these rifles as a business as I wanted nothing to do with what was imported by most importers after 2007. I evn had the opportunity to purchase at discount, many warrant return rifles to pick thru for serviceable parts so I really got an indepth view into the 2009 thru 2014 imports and the issues they were arriving on our shores with.
I've spread the advice and gleanings from my experience but a lot of folks did not and still don't want to hear it.
OP, your friend's rifle is no different than any other 2007 and older, there is nothing that makes it more valuable and if it is in excellent condition with a low round count and it's issued accessories a fair value would be around 750.00 or less.