Here's a more detailed answer (my first was from my phone). Unless Ludwig has changed the design since first introducing this rail the new rail is somewhat longer (1" or so) than the old style rail, therefore the holes do not line up. The lower grip on the upright is also too big to fit within the confines of a vintage rail so you can't mix old with new. Finally, the new rail is not a particularly "gig friendly" design. The ball mount is cool and it will hold the tom where you want it but the arm cannot be folded flat against the drum when tearing down. To pack up the bass drum (assuming you don't want to use a super oversized case or have the arm protruding out of the zipper on a bag) requires that you remove the upright from the rail altogether. This isn't a huge deal I suppose but still not ideal and the potential to lose the internal spring or a washer on a dark stage is always there.
Frankly, the later version of the Ludwig rail pictured below works just fine. That is the version that Maxwell has reproduced and is readily available, as are vintage examples. I'm talking about the style with the ratchet type angle adjustment and the eyebolt gripping the "L" arm. I assume you currently have the "telephone dial" type of angle adjustment on a '64 set and, while those can work just fine, they are much more frustrating to use. Probably why Ludwig revamped the design in 1967.
I have the newer Ludwig rail like you're considering on my Element SE kit. It works fine but if the holes were the same I'd put the vintage style mount in it's place without a moment's hesitation. The new version is just bigger and bulkier than it needs to be to do the job at hand. The ball adjustment is nice but doesn't outweigh the negatives (IMO).
I recently purchased a brand new Classic Maple kit. The bass drum was "virgin" but it isn't any more. I drilled it for a vintage style Maxwell rail and it works like a champ.
If that doesn't appeal to you then look into an Atlas Arch. Also kind of bulky but it also has a ball arm and doesn't require any drilling. I have one of those too and would choose it over the bolt on one if I was going "modern".
