March 17, 2008, 16:15
Lindell V. RiddleKen,
Except for the occasional mistake or a possible mis-marking situation where just one digit is wrong it is fair to say that nearly all cases left the factory with numbers properly matching. Innocent mistakes could occur later at the retail jewelers, when two identical watches are opened for service or even by sellers today when identical watches are being offered for sale at the same time.
Most of us are very careful to avoid buying "mixed-up" watches and we use extreme caution to guard against such things happening to watches in our collections. A situation such as you describe, having mismatched case components has a dramatic effect on overall value. It is something to be careful about when buying and protect ourselves by pointing out the matching numbers when selling.
Some case makers used Roman Numerals as a form of code along with Arabic Numbers but the case should stand up to scrutiny. As an example in the image below, case number 8914275 is inside the case-back. On both the case-frame and bezel we find the last five digits clearly marked. A correct match.
Claiming... "that Illinois was getting rid of old stock and sold them" ...mixed-up is like a... "the dog ate my homework" ...story. In other words, it just doesn't pass the laugh test!
Always verify the numbers when buying or selling...