Look in Resource Manager for a PC > View > Inventory > Basic Inventory. Select a Data Class then click on the Status tab and it will give you the table name. All the Basic Inventory ones are Inv_AeX_AC...
Inventory from Inventory Solution is separate, you could in theory have an Altiris system with no Inventory Solution, say just Patch Management or Software Management, in that case you'd have Basic Inventory but none of the other Inventory tables.