I have been asked what is the best way to capture previously designed gearbox in AutoCAD and having multiple layouts for a range of serial numbers as the product was improved as it was reordered in Solidworks. I have attached a screen shot of the layout as I am explaining here.

I am thinking that the use of configurations would be used in the assembly of the model of this gearbox and additional detailed tabs stating the serial number would be used. Others think that it would be a matter of history recall because switching between configurations would mess up the detail drawing and balloons for the serial number range for the gearbox.

I am asking for advise on how everyone seems to be handling this type of modifications as it comes up. Is there a better solution to this that we have not thought of?