Chef,
Not that I know of in either right or left threads. The early post-war small head rods were still right hand thread until 1959-1960 depending on model. I'm not aware of any special runs or commemoratives that used a large head. If you have a scrap pre-war rod, you could get creative. You could drill out and cut off the large knob tip, then silver-solder it onto the end of the left-hand rod.
I assume you're putting a modern cylinder in a pre-war frame with pre-war barrel. I've probably told you before, but I've got a similar project on my bench right now too. Only difference is that my post-war parts are early ones. Mine is a British .455 frame, Model of 1950 Target barrel (with ejector rod shroud) which I shortened to 3.5" and ground the target rib off off. I'm fitting it with dual cylinders. I have a new old stock 1917 .45 ACP, and a re-chambered post-war .45 Long Colt cylinder (which must have come from a post-war .38 Heavy Duty). Luckily my Long Colt cylinder has an early extractor with right hand threads.
I've also replaced just about every internal part. It's going to be a very slick retro carry gun when I get done with it. I'm planning on trying my hand at rust blueing.
Almost forgot, I ground the grip frame down to K frame size and fitted it to a pair of very nice pre-WW1 large medalion K grips.
If I can be of any more help, just ask. I might even have a part or two to spare if you need something.
Good luck,
Chris Taylor
