Mr. 3000 - A Milestone and a Giveaway

Today, April 28th of 2014, the latest incoming shipment from COMC put us over the mark.  We have finally reached 3000 unique Griffeys!

Here's the card of honor:

2008 SPx Ken Griffey, Jr. American Hero #KG43 #/725, we salute you.

This guy.  It's no surprise to me that it ended up being one of these 2008 SPx American Hero insert cards.  I've been powering through the checklist when I can find each card I need for a dollar or less.  I'm getting pretty far, too, as you can now see in The Beast.

This shipment brought us to 7,542 total Griffeys with a total of 3,025 unique cards.  That's a duplicate ratio of 2.493.  The stats of the shipment were 84 added, 76 new, and a dupe ratio of 1.105.  That's the lowest yet from a sort.  There were a few stragglers mixed in there with the COMC purchases, so it wasn't a perfect 1.00, but it's still a massive step in the right direction.

You may have noticed that I blacked out the number of this particular card.  That's because in honor of this milestone I figure it's time to have a giveaway.  Winner gets a prize package of cool stuff assembled by yours truly.  Here's the poop:

Guess the serial number of this card.  Closest without going over (yeah, it's one of those) wins.  Hint: the answer is less than 726.

Comment below with your guess.  I'm going to let this one roll until Friday at midnight CST.  If you are venturing a guess and we haven't traded or communicated via e-mail or anything, go ahead and e-mail me at tjv504 at gmail dot com with your deets.  Good luck!

Don't look for an imprint of the serial number here - I checked.  It's clean.