I changed these things on my 1951 car a few years back – can’t quite recall where I got them or what the part numbers were – but I’m pretty sure the CTA part is 6680045 – WIPER SPINDLE RUBBER OUTSIDE. The picture looks right. You might also need the CHROME CUP WIPER SPINDLE OUTSIDE – 680049 which sit on top and brighten things up.
The job is well worth doing – it stopped my leaks. When you put it back together be careful that the whole assembly is central (there’s some float in the bushes) – otherwise your wiper sweep will be asymmetric which, unless you decide to bend the wiper arms, could mean you wipers hit the frame. This can lead to your wiper flying off into the bushes on a dark wet night never to be found again. Apparently.
Chris