We're hoping Titleist will let us know, but most likely the dark red numeral was the 2014 NXT Tour.  Mine were consistently 2-3% further than the 2012 NXT Tour.  I've been working on increasing spin around the green so I'll check once we thaw if I can see a difference with the ProV1X.  When tested, the performance was the same for me.  Both better than anything else I've used from green to fairway.

i got test balls 2 years ago right before they launched 2013 prov1 &1x.  (i have prov1s as my preferred balls) i didn't get anything last year and it makes sense.  they didn't launch new prov1s, they launched 2014 nxt lines. looks like balls were sent to people who have NXTs as their preferred balls?

Hey Don, they should work well. My test balls were red lettered last fall as well and I did some short game tests against Pro V1s and Pro V1xs and they were very comparable. On full wedge shots they spun a little more than the Pro V1xs. 

Thanks - great news.  All I need is one or the other in optic yellow so I see how far they go.

I'm guessing my  yellow test balls were the new NXT-S.  It is the best "feeling" ball I've ever hit.  I actually prefer them to anything I've ever hit

I'm not sure but I'm hoping I will get some test balls to try out.

I, too, received a sleeve of test balls from Titleist, I believe they were Velocity balls.  However, as soon as I received them, I went into surgery to have my knee replaced, and, so I didn't get to test the balls.  But Last Monday, I played for the first time in a couple of months and used these test balls for the full 18 holes.  My first impression was positive, in that I wasn't the shortest off the tee.  The first ball I played found a watery grave just 4 holes into the round, but the other one stayed around until the end.  The cover seemed to get a little roughed up although I did not hit a cart path.  It played as well as my 2012 So-Los, but the SoLo cover is more resistant to scuffing.  I wish I had received the new SoLo balls, instead of the Velocity balls.  I like them better.

Didn`t get any this past fall but did get a sleeve in the spring and I think they were Velocity`s. They went a mile but I couldn`t stop the ball on the green unless I dropped it straight down.-Chas B