A single unified table should be used for inventory tracking. There'll come a point where you need to generate reports based on your entire inventory and this will become a very difficult to impossible thing to do if you have multiple inventory tables instead of a unified table. Your Base Asset table sounds like the correct way to handle this. Define an auto-entered serial number in it as well as fields that are common to all inventory items.
Consider this method: I once worked for a company that manufactured or processed both wine corks and bottle caps. These are very different products with very different manufacturing, purchase and quality assurance specs. Yet we had a single unified table of all corks--natural and synthetic, screw caps and the materials used to produce those screw caps as well as other very different products. The DB system handled those differences by having a number of product specific tables for documenting those details that were linked to a central inventory table. If a record in that inventory table was a cork, the match field for cork manufacturing details matched to a record for those details. If it was a record for a screw cap, that match field was empty....
Thank you PhilModJunk,
I can proceed with more confidence now :-)