I recently acquired an M16 solid butt stock (no trap door), and I noticed that the plastic has a duller, matte-like quality when compared to my handguards, which seem more glossy. I also looked at photos of several finished retro rifles here on this forum, and noticed the same thing in several of the builds: flat black butt stock and glossy black handguards.

Does anyone know if you can determine when the furniture was made, or by whom, depending on the luster of the plastic? Is one preferable to the other when building Vietnam-era replica rifles? Or am I being way too picky about this?

All the new furniture that I have seen was matte. The older used stuff started to shine up some. Still looks cool either way!

I believe the Matte models are original old stock (not used in field).  The glossy ones were in the field and natuarally buffed to a glossy finish.  I five or six back ends of Matte Stocks that I cut off to make 607 stocks and I just buffed that cut piece to a nice shine with a buffing wheel.....worked pretty nice.

I had suspected that the glossiness might be due to use; thanks for the replies!