Basically, he can do *zero* cleanup. Most sword collector will not mind a correct re-wrap, but virtually any cleaning (even oiling!) will destroy the value to most collectors. I'm not saying that I agree with that, and in fact, I have written an article for a sword and bayonet collectors group advocating that they change this mindset, as they are not taking appropriate action to stop degradation of these pieces of history. Its been published somewhere on the internet. I come across the article on a website every once and awhile.
As to swordmakers manufacturing U.S. pattern swords, there were literally hundreds, both American and foreign. Follow the link to a 19th Century sword discussion board. You will probably find someone there who can pickup on the clue of "XXXX Tool Co." The leading experts in the field of Civil War swords frequent that board.