I have been told several times that there are some differences between the post-war lightweight adjustable stem and the pre-war ballooner type adjustable stem. I've never owned a pre-war Autocycle, so I don't know, but the buyer needs to look carefully before spending $300 on a stem that it is the right one. I have seen a number of times where people try to buy the adjustable stem off a Continental and leave the rest of the bike (or part it out), presumably because it's close enough to the pre-war ballooner variety of the stem. The ironic thing is the post-war Continental will ride rings around the pre-war Autocycle, but that's another story...