HB   1965   327   300hp   4bbl   w/Std trans., High Perf.
HB   1966   327   275hp   4bbl   w/A.I.R.
HB   1967   327   275hp   4bbl   w/A.I.R.
HB   1968   327   275hp   4bbl   w/H.D. clutch
HB   1969   350   300hp   4bbl   w/Auto trans.

A casting date of February 25, 1968 would suggest a 275hp, 327, probably still a Camaro engine. I would still double-check the casting number. While it is possible that a Feb. '68 block was used as late as the '69 model run, it's not likely, unless there was a problem with the block on the assembly line, and it had to be returned to the "heavy repair" section to be repaired, and then put back on the line. An example of a block that would have to be returned to the repair area would be one that had a bolt(or several) broken off in it. It would be pulled off the line, and taken to the heavy repair area, and, if it was repairable, it was. Then, it would get put back on the assembly line for use in another vehicle.
If the engine block had already been stamped with the VIN derivative for a car, that number would have been ground off(with a pencil grinder), and re-stamped.