If you want to know if a customer has purchased specific items, you can view all the serial or lot numbers sold to the customer.
Open the Customer Card window.
Browse to the card for the relevant customer.
Click Sales, Item Tracking Entries.
Set a filter on the Item No. field to see the relevant entries in the Item Tracking Entries window.
You can also use the item tracing feature to see all customers that a specific lot or serial number was sold to.
Viewing Serial/Lot Numbers from Vendors