Paul, Some quick checks of my resource documents comes back with:
Casting# 3994258 = 1963-72 292
CON 2 = Assembly Plant Conveyor# 2
Block Casting Date Code L 101 = L - December, 10 - 10th Day of December, 1 = Build Year - 1971 (this would likely make it a 1972 model year engine)
Serial# F124TKL = F - Flint Plant, 124 = sequential number, TKL (called an engine "suffix" code) - 1971 & 1972 292 CID 6 Cyl - C10, K10, C20, K20, Suburban models
The serial# and casting date code pretty much confirms this should be from a 1972 model year truck. I think this give you what you need.
