Yes. Items can be included in the auction but not shown online. They can also be included and shown but excluded from bidding.
1. From the auction page editor, click on the Auction Setup tab.
2. On the item to hide/unhide, click on the edit icon in the bottom right corner of the item window.
3. Under Exclusion Option, select Exclude from online if the item is included for internal bid assignment and checkout.
4. Select Show online, Exclude from bidding to show the item to bidders, but keep bid assignment internal only from the Auctions grid.
5. To open bidding to all bidders, leave the field Select Option blank.