Yes… but no…
It only shows the items that you have downloaded, not all the items purchased.
So if you have items that you have purchased, but not downloaded, there’s no easy way to find them.
Edit: there’s only one method to actually know all the items that you purchased. Go to your account on the Unreal web page and go to Payment History. That’s the only place where they are all listed, but you’ll still have to search each item by hand as there’s not direct link to it.