The frame and engine on my 1/71 K0 are 243737 and 243668, so your frame is late K0 for sure. The engine is several months younger from 1970 and most likely belonged to a frame with a closer VIN.I recently bought a red CT70 K0 from CHP. The frame# is 276787 and the engine# is 224729, with a mfg date of 7/71. Am I correct that this was among the last of the K0's made? I think Polson's book says that production of K1's started in 8/71.
K0 VINs went up to ~285xxx so, yes, it's a very late K0...probably within the last month of production. Not so sure about the engine SN, they're usually within about 500, or so. It's still a K0 motor.
That's a K0, one of the last manufactured. K0 VINs never reached 29xxxx and K1 production began in 09/71.