Originally Posted by Wes RS
Lambchop - the J1 and J2 are identical apart from the paint work I think, the J1 has the proper rising sun style where the J2 has the pattern more spread out along the fairings
Easiest way to tell is by looking at the tank, if its got a black top its a J1, any other colour its a J2 or even a A1P (636) but it will say that on the fairing
I paid £2250 for my 5600 mile J1 on an X plate, I would say your mate paid a bit too much for his...
John you paid just about right I reckon, I got mine fookin cheap really considering the mileage
J1
J2
A1P (636)

I never could work out the difference between the J1/J2 until you explained it.
Sounds like you got a good deal! I wish I had bought mine 2 months ago when I was looking at them as they have shot up in price since Chrimbo!!