You're welcome. As far as the numbers go,I would think that anybody who knew the sequence of numbers has long retired
As far as inner covers go,depending on the year the earlier (mostly rigid frame models..but not the late rigid frame models)outer covers have one bottom screw hole in a different location than the later models...although the cast number stayed the same T411.
What year transmission do you have and what year is the bike?
I imagine with that many, you'll most likely have an early one that you will be able to see the difference in.The early rigid boxes also had a mount that the later rigid and swing-arm models didn't have. Unfortunatley, I don't know what the changeover year was. Nonetheless, they will work.
G,Day The early post-war, rigid frame gearbox mount castings are noticeably different than later models. The early boxes were prone to cracking so they beefed up the mounting areas. Also the early boxes have large numbers stamped on the exterior. In 1948 they began to tap the two bosses on the back of the box, just behind the drive sprocket, in order to accomdate an external speedo drive due to the introduction of the sprung hub wheel which could not accomodate a speedo drive. In the early 50's the boxes were changed to accomodate an external speedo drive. Hope this info helps. With so many boxes you should be able to group them according to the changes described. Cheers Dan O.......