The Serial number must be stored in the BCU/top cover. Since this cover is not the original one (it's one I repaired on exchange basis), I doubt it'll tell you much. Also, most of my customers want to remain anonymous since they don't want public knowledge that their bike had code issues when trying to sell it. And everyone's starting to sell now that the Stark Varg is looming. That's why I'm selling all my Altas (both gone) and parts before the bottom drops out.
Very cool, I tell everyone asking for their packs to be fixed to talk to you as I'm getting out of the Alta/Electric bike thing.