Unfortunately these are the only photos I have of the markings themselves. This is actually a US "private purchase" waistcoat. And if it helps The long digit number is located on the liner of the right armscye, in the front lower part of the curve. And the 4 digit number is located on the liner as well but up near where the liner meets the collar. The only other photo I have would be this one of a number 36. Which I'm assuming that's the size of the vest itself since the measurements I took of it match up to a man with a 36" chest.
View attachment 453315