|The following is based on Fallout New Vegas cut content and has not been confirmed by canon sources.|
The only mention of the weapon is in an unused form list used to determine what items can repair what. The form in question is called RepairNVHeavyRiveter, but contains no entries. Judging by the name, the riveter would likely be a weapon firing rivets.
The heavy riveter cut from Fallout: New Vegas.