Phcctech: welcome
That was answered correctly in this post on 7/24/06

Quote
Originally posted by ev607797:

3. The 8A, B or X-series buzzer was typically mounted beneath the left-hand dial mounting screw in most sets, although the early buzzers had two mounting holes and 83X/283X sets actually had plastic bosses in the base to allow them to be screwed down.


Retired phone dude