Since we're discussing parts and Williams brass, just to be clear, I do not believe that Samhongsa ever made a Williams Dreyfuss Hudson. They made a lot of nice, basic brass for Williams (4-6-2, 2-8-2, Niagara, N&W J, others) during the Williams (and Weaver) Brass "golden years", but the early Wms Dreyfuss (not a great loco, but very "improvable" - I have one) were made by someone else (China? Samhongsa was Korean), based on its "fingerprints" and marginal construction.
The later, high-end Williams "Masterpiece" Dreyfuss locos were made by someone else (3rd Rail uses/used them too, I think) - well after Samhongsa exited the O-scale model locomotive business.
Or so I believe. Doesn't find you a rod screw, though, does it?