You need resistors on old Bally's to get rid of the flicker, the diodes serve a different function. You can either add them yourself individually to the sockets (very cheap but time consuming) or add a daughter board of resistors to your existing lamp driver (easier than the former but still cheaper than an all new driver)

Seems neat to have a couple in the parts box, but it seems expensive to redo a whole game with those. $1.40 per insert lamp (plus labor) adds up quick compared to Comet's daughterboard solution. Also it wouldn't work for any controlled lamps above the playfield, like chase lamps on games like Eight Ball Deluxe.