Nothing special about a 12/13, because nothing much has changed over the years. Frames basically all the same, changed to the current round tube in 2009. 2001 to 2008 had a more oval main tube. Check for any cracks around the head tube or any that have been welded up. I think the white framed ones around 2014 had a few frames crack. Steering geometry has stayed the same, unless the triple clamps changed. Forks changed from marzocchi to tech in 2016 i think but the Raga had them a couple years earlier. The marzocchis were a good fork. Same base engine throughout the years, the pro came in 2001. Ignition makes changed over the years so a bit of pot luck regards availability. The Raga/GP were slightly better specced as opposed to the standard/racing, with a better shock (Reiger or ohlins vs sachs) and forks (tech vs marz) and carb (keihin vs dellorto). If you're a clubman i would choose a cleaner standard model over a rougher raga/racing model every time. Id actually stay away from a raga because they have magnesium crankcases that sometimes broke or could be starting to corrode now. Very little difference performance wise.
Personally id be looking for anything post 2010. The later frame, and from then the bikes have all been pretty reliable. Earlier years had variable clutch issues. Id pick what looks the best price wise for condition. And dont be swayed by a Raga or GP, unless a similar condition and price
I may be slightly incorrect regarding naming, but for many years you had the txt pro and the raga edition. Then when he left i think it became the txt pro and the txt racing. Then they dropped the txt pro (marzocchi and dellorto model) and then had the txt racing and txt GP.
Ive had a '10 '12 '15 '17 and a '21