I'll be joining the thread, @MatthewAccenttMarble.

Yes. When you export the IIF to your QuickBooks Desktop account, it'll update your existing Item list.

Here are some articles to help you in the future:

• Turn on Advanced Inventory
• Tasks you can do with IIF files

Please don't hesitate to leave a comment down below if there's anything else I can do to assist you. I'll keep an eye on your response. Continue to be safe and healthy. Have a good one!