Welcome to the Quilting Board!
I'd love to have a blue clone, however all the ones I see on ebay are priced far into the stratosphere.
(Hi. New member.) I thought that the 337/338 Great Britain Singers are all-metal. I don't have access to my 338 at the moment, but I don't recall seeing any plastic/nylon when I opened them up to oil. (I gave a 337 to my niece.) And I've read comments on VintageSingers and reviews elsewhere that say they are all-metal.
I own a powder blue singer, purchased in 1968. It still works great, although I now have several more. They are still out there. I see them on Ebay once in a while. Good hunting.
You got a great deal. I'm afraid I'm a purist and love the black ones - but, I would have bought the blue one, too.