I bought a new TI in July 2012 (my 3rd TI) I just walked out and looked at the bar code sticker on mine and it says 7/11/2011.
Things to look for to make sure you have the most current design.
1. The front scupper holes have black re-enforcement plastic sleeves (these really help)
2. If you look at the AKA bars where the knuckles attach to the tubing, you will see that the knuckles are now glued and riveted at the factory (this was a big design problem, and the rivets began to fail after about 6 months to a yr of use, all fixed now).
3. If you look at the Mirage drives, you will see they have extra pegs to make them easier to get into the hull, there are also corresponding slots in the hull.
4. If you look at the front AKA cross bar, you will see that the bearing plate (with the delrin bearings) is now welded in both the front and back, this is much stronger and should give you no problems with the welds cracking (only a small number of very early AKA X-bars actually failed (mostly 2010 models, you can tell if it's an early one if the bars are painted, all later bars (anodized instead of paint), had much improved welding.
5. If a Hobie emblem is embedded in the top of the bow, these are parts from their latest mold, the bow is slightly narrower, and about 1 inch shorter that the hulls from the previous mold, and a little stronger, with better seals around the main hatch.
6. Look at the seals around the front hatch, there should be two (one piece extruded foam rubber seals), one on the lip around the lid, and another around the inside rim, they call these the vertical seals, and they are far superior to the earlier crazy glued tubing they used before.
7. Look inside the front hatch at the X bar bracing down at the bottom of the hull, the small 1/4" dia stud with a nut on it should have a screw driver slot on it. This is a much improved rolled thread stud made out of the highest grade stainless available.
8. Look inside the rearmost 8 inch round hatch. You will see the rudder tubes are neatly tied to clips on the underside of the hatch. What this does is prevents water from entering through the rudder tubes by creating an air bubble in the tubes when the rear of the boat is submerged (usually a good sign that your boat is grossly overloaded in the rear, when it's underwater). While you are in that hatch, hang the extra rudder pin you should have received with the boat inside that hatch (with the metal ring through one of the holes in the rim of the hatch). Do yourself a favor and pre-bend the end of the metal ring so you can get the darn ring off if you rudder ever breaks while out on the water and needs to be replaced.
9. Look at the bungy cords that hold the AMA's onto the AKA bars, they should be 5/16 dia bungy cord (used to be 1/4" bungy cord), Look up Tom Kirkmans improved Bungy design on this forum, his ideas are usually pretty darn good.
If your boat meets all these conditions congrats, you own the best engineered and fun boat on the market today, and you will have years of trouble free fun if you take care of the boat.
I suggest rinsing the boat with fresh water after use, and lubricating the Mirage drives with WD 40, after they have been cleaned. Try to put everything away dry whenever possible. One thing I did when my boat was new was to use krylon clear coat spray paint on all the metal (inside and out). This helps with the galvanic corrosion of the rivets if you soak them down when the boat is new. I typically use a good UV protector on all the plastic (Hobie recommends several).