The upper half with the springy contacts pushes the contact disc into the bottom half.
the repro contact disks work ok. The repro switch bodies in general do not. Occasionally I hear of one that does, like MrTube's post above. Maybe they're getting better, but all the ones I have used were unreliable. If you want an original, you can find NOS 32's and replace the lower half with one for an A. You can ask Bert's in Colorado if they have an original, or you can ask Dan Bixby. Dan re- cad plates them and sells on ebay under the seller name phonconn.
Can I buy just the new contact disk and connect my existing wiring harness to it?