I recently purchased a Hamilton Brandon cld. I had some trouble identifying it because it has a 982M movement in it. I used catalog links on the Vintage Hamilton site to identify it. I don't have pictures of it right now, I shipped it off to my watchmaker, then I found the Vintage Hamilton site. How common was it to upgrade the movement and was it likely to have been done at the time of purchase? How effective was the cld system of sealing? I understand that the question is moot because of the unavailability of new seals I'm just curious about the technology.