Very observant, the sequence number. And what does that signify?
Given the variances found on sheets, it may be easier to explain SO numbers and VONs...
There seems to be many meanings and variations to the BS sequence number. Each plant and year can different (imagine that....).
Some plants appear to be sequential in that the number increases roughly consecutively throughout the year. Some plants seem to be date coded and show a daily work flow. Some plant just seem to show a daily work flow without any date code. Some plant appear to use this as an inventory and counting item i.e. the sequence number will be much lower on a Rally Dash than other sheets in the car indicating the sequence number was a counting of the number of Rally dashes built as opposed to standard dashes or total dashes.
You can have two sheets from the same car that do have the same sequence number and cars from a different plant will have two different numbers.
The general gist appears to be the number is a daily inventory/counting/administration of that particular department. In the cases above, we're looking at the upholstery/seat department.
I'm an employee in the department. I come back from lunch and find the printer is down. I still have to do my job and match up my inventory of seats to the projected assembly need for the afternoon. I grab my grease pencil and a stack of unprinted sheets from the printer as my scratch sheet/designated piece of paper I'm supposed to use to do my job. I check my master inventory/work guide for the day and find my next next inventory items are for cars with Sequence Number 3200 - 3210. I have to account for my days work and production and match up the proper seat to the car. So I write the numbers and the appropriate trim code on the sheets, grab the correct seats I need, stuff the sheets in the back of the seats, put the seats on the conveyor/hand cart and move on. I've managed my inventory and done my job without having a printed sheet.
Another reason why to save as many sheets, tags, window stickers and factory documents as possible....