The crates did not have the numbers stenciled on them originally. That was something that occurred later, perhaps in the 60s. The one thing I have observed is that most had the serial number on the inside lid in grease pencil, however I cannot tell you if that was from the factory or done while in the supply system.
An unaltered crate will be the pale green with no NSN or serial. Later the crates were repainted glossy olive drab and often the serial number and the NSNs applied.
The crate shown in the first post is the unaltered type, although I do not see the serial number written on the inside lid.