Stamping the block with numbers which match the VIN, supposed engine and date codes of the car is making the numbers match, of course it is in theory but in reality it has achieved nothing. It does not make it a "matching numbers" engine to the car. What we are talking about here is taking say an "ME" coded block and then after the machine work transforming it into an "MO" block. I don't see how that works?
I am under the impression that in Camaro judging circles and please someone step in and correct me if I am wrong here, that a car which no longer has it's original factory installed engine, but has a block which has the correct code, a date close to the build date of the car and also has the VIN of the other car along with it's original factory stampings in place, then that car is acceptable for judging. Naturally it would lose points for not having the original block. In a case like that neither the car or engine are misrepresented at all. It is for example a 68 Z28 that still has an original MO block, but not the one the factory installed. No the car would not be presented with it's "original" engine but it would not be a "re-stamp" either, I know which one I would rather have!
IMO, "Matching Numbers" is one word short, it should be "Original Matching Numbers"