If there was an early time when pushbutton phones used pulse dialing, it must have been brief. All of the pushbutton phones that I ever saw as a kid were DTMF. I'm not sure how a pushbutton pulse phone would have worked without digital electronics. This was at a time when, in the US, the phone company had a monopoly on phones, all phones were rented, and you actually paid more for "touch-tone" service.

Later on, the phone regulations were changed, and you could own a phone. That's when cheap pushbutton phones came out, that had a switch allowing you to choose between pulse and tone dialing, because you still had to pay more for touch-tone service and some regions didn't offer it.

The weird thing was, sometimes you had to use both, for instance at my college, the phone system used pulse dialing, but I had to enter a "calling card" code using tone dialing in order to call my parents and put the call on their bill.