OK I have almost finished building my FN,  M16A2 clone. I used a black FN upper receiver (from the EE), a lightly used GI FN barrel (from the EE), an FN bolt (from the EE), and black shiny hand guards (from the EE). It is not going to be a perfect copy because the bolt carrier is ICE and the lower receiver is a Matrix Aerospace with a PSA - PTAC lower parts kit (which had a great trigger out of the bag by the way). Anyway the last decision I have to make is the butt stock.  I have a GI black shiny stock and a commercial grey matte stock.  The black shiny stock would visually match the hand guards but which one would be more correct for an FN build?

rub some oil on your gray stock, it turns black. for what it's worth, my issued A2's all had the "textured" stock, i.e. the gray one.

Same here.

Thanks guys, that is what I needed; true field observations.

Good idea putting oil on the gray stock. I got my stock form RRA and would like a darker color

The newer DPMS and RRA "A2" stocks will not "blacken" up with a little oil... They will get to a slightly darker grey at best.  Being a retired Combat Arms NCO, I clearly remember that on the M16A1s and M16A2s the stocks would turn black with a light coating of Breakfree.  The newer stocks  from DPMS and RRA are made of a different grey plastic and not the same type as used on the older USGI A2 stocks.   The only completely "black" stocks I've seen lately are from Armalite and the Chinese UTG (??) brand, which both appeared to be of lesser quality than the other two makers.

Heck, I even tried the black shoes polish wax with zero luck to darken my RRA stocks and I even had somebody try to dye it black, which was a no-go as well. At this point, I figure that I'll need to either learn to live with the dark grey A2 stocks or try to have the bodies Ceracoated in black...  I hear that this product is very hard when properly applied and resist lite to medium scratches.

...If anybody knows of a trick to blacken both DPMS and RRA stocks, please pass it along...  I'm trying to build a correct looking 1985/86 period M16A2 clone.  I have the shinny handguards, but need a matt black buttstocks to finish the look I'm trying to achieve.

Not just oil, but "Breakfree" aka CLP. In basic, they made us coat the outside with CLP, to prevent "rust", even though the receivers are aluminum. Stock was left dry.