The transaction will always be recorded if their system makes any kind of sense - on theEPOS system I use, as with all EPOS systems I'd imagine, I can see sales per item e.g. I can see I sold 3 widgets yesterday, one at 11:05 and two to the same customer at 14:23. I can further drill down to see the receipt so I can see what else was bought with the widgets. That data always exists because it's part of the sales data for that item.
The only question is how much effort they will put in to get it - I can get that data because I have full access to the back office, but the staff can't (although if you can give them a time and date they should be able to find it, but it takes ages)