Dean, You are correct. Guns were made in serial number sequence, by batch. The batches being in multiples of 25 usually. In a few situations, a batch of serial numbers were "set aside" for future uses and guns made in those set aside numbers would be made in a special run at a later period. Yes, 12345 was made before 12346.
The factory did record the serial numbers, by dates, when they were made, mostly for guns made up to the end of about WW2. A partial reason for this is that payment for guns produced was the way workers got paid, so it was necessary to keep track of how many guns were made each day and that was the job of the Floor Foremen to record numbers made each day, by serial number batches. The portion of these records that survive, are not in the factory archives at the CVHM ( except for the Safety Hammerless models which I helped arrange to have donated), but are held by private individuals. Guns made for test purposes or by custom orders, like the .357 Registered Magnums, or special orders in the Service dep't. will not always follow in serial number sequence,as did the floor produced standard production guns. Hope this helps. Ed.