Williams used the wireform on a couple pre-flipper games including Cyclone. The most memorable and desirable flipper game with a wireform habitrail is 1953s Williams Skyway.
Quoted from Pinball-is-great:
This summary sheet of pinball milestones was being handed out at Texas Pinball Festival (or Houston Arcade Expo) last year or 2 yrs ago. I believe Mr. Dan Ferguson was handing out pinball info during his e-m pinball machine trouble shooting class.
The list shows Bally as introducing the pop bumper, but I can't find any reference to what game it was. To the best of my knowledge, Williams Saratoga was the first.
Quoted from pinhead52:
1963 SweetHearts last of the gobble holes...
San Fransisco was the last.