N on a front sight (behind the front blade) is a Neidner sight. A NN front sight is a National Postal Meter sight made by Neidner. Alot of Inlands wore the N front sight sight,I am sure they had a contract with Inland, they probably made replacement sights that went into the supply chain also. Late in Neidners contract,they could not meet the requirements and Rudy Furnace took over the contract. The letter R was stamped in place of the N (another misconception that Rockola made the front sight).

As far as the trigger housing, I would yes on the T2.