To clarify, and as you allude to a bit, meat will "absorb" smoke for as long as there is meat in the smoke environment. (Properly, we should probably say it "adsorbs" smoke.) Point being, the chemical reaction (myoglobin and NO2) that we witness by placing meat in a smokey environment stops once the meat reaches a certain temperature, but the addition of "smoke flavor" to the meat will continue as log as it is cooking over smoke. We typically want to guard against the bitter, sooty taste that may happen as a result, especially with a strong wood or delicate meat.
Joe Corday, the Meat Extension Specialist at Iowa State's Meat Lab had a nice brief on the subject many years ago if anyone would like to go read about it.