I can't answer that question but I think a likely scenario is that they didn't control inventory like companies do today, it wasn't first in first out, and I'm sure items were misplaced only to be redicovered later to be used when found again, etc. I'm sure they pulled inventory at random in many cases.

Your engine likely just sat around a while before getting either assembled or shipped as in Ademons case, his sat around assembled from November all the way to (April or May?) before being installed.