wr426f throttle stop mod??

[bakeyz426f]

how can i tell if my 01 wr426f has the throttle stop mod on it? my old ride was an 02 yz426f and it seemed to rip a little harder than the wr426f i have now. i want it to wheelie it third again instead of first and second only. it trys to lift it up in third but doesnt rev enough or mabye just not as much power. i recently hooked my wr426f up with the 2002 yz426f suspension to make it good for jumping. now i want to check the bike to see if it has the throttle stop mod done or not. i think it might not because i just got the bike and it seems all original, tires, stock handle bars, and it still had the air box lid attached when i got it. however the stock exhaust was uncorked. just want it to rip a little harder. also i put my old yz426f wheel on my wr426f because the rear tire on it when i bought it was 50% tread and my old wheel had 90% tread on the tire. now i think my chain adjustment is off because when i tighten the axel nut to the rear wheel it makes the chain get real tight and the wheel hard to spin. if i tighten it just a little bit more tight than you could get it by tightening it by hand it seems to give the chain enough slack and the wheel turns ok. does this mean i need to adjust the chain tension? heres a pic of the bike. any advice is much appreciated.