KL tubing was butted 0.7/0.5 thickness, should take a 27.4mm seatpost. Is a 27.2mm post a somewhat loose fit?
You can always cut the frame up and measure the thickness of the tubes to determine origin! You might also try tapping a tube and comparing the ringing sound to another similar constructed frame of know tubing type. If you can find a frame known to be made of SL, then a KL tube frame should ring a higher note. It should also be very similar note to a 753 frame which shares 0.7/0.5 butting, an 753 frame is just much stronger (but no stiffer) due to heat treated tubing.

Another KL tube thread over here http://www.bikeforums.net/archive/in.../t-535395.html