Pat, nothing. Going to leave it as is, I'm not that big of a rivet counter and the Williams model isn't all that tapered.
Thanks Bob, I looked and saw they had ACL listed but thought it was an error, didn't know they owned any USRA Mikes and didn't see a photo of one so I'll take another look.
The running boards are the one BIG thing that I see as possibly having to move/replace, but man I hate to do that, although I just got thru Dremeling them off a MTH 4-8-4. At least the Mike boards are soldered in place.