Hi Kevin
Not sure about engine numbers, but the chassis numbers for 1968/9 production were CC25003L to CC32142L, with 1970 starting at CC50001L. As I understand it the engine numbers are pretty close - mine is less than 100 higher than the chassis number (that's a 1975 car, though). Someone may have the actual engine numbers, but I haven't seen them listed in any of the books I have read.
Hope that helps
Alistair