Welcome to the forum!
We changed-out one a while ago, and that was the only one I have come across in 25 years.
We held on to the branch breakers, God knows why, and I can't remember the buss layout of the panel. I'll have to look in the shop & see if the CB's are still around, or they found the way to the dump!
Push-Matics were not a 'big' item here in this part of NJ, although we come upon one occasionally.