Sony KV-1217 button replacements?

[aapljack]

I picked up a well-loved Sony KV-1217 from the Goodwill bins recently. The set powers up, but was stuck on channel 12. No matter what other channel I tried to switch it to, it always went back to 12. I tried the channel tuner and even hooked up a VCR while the channels were being found and no luck. I may not have been doing this correctly, but I went ahead and pulled out the PCB that held the buttons on and started inspecting the buttons.

Once I removed the channel 12 button, I noticed the rubber gasket's center part had come detached. I popped open another button and it was in similar condition. I was thinking of just replacing all these buttons with new ones, but I don't know what I am looking for or if they are still being produced.

There are two different numbers on them. Some are 04ZA and some are 23ZA. I tried looking up these part numbers, but didn't come up with anything. They are also marked with TOKO and Japan.

Are these available somewhere or is there a suitable replacement?