The 455's do blink at different rates but I actually prefer a longer buzz time. It should be loud and somewhat annoying. It's supposed to draw attention to the fact that someone just turned the machine over, A quick little 1 second buzz would defeat the purpose. It is also a different sound for EM's. Bells chime for points being scored. Knockers knock for free games or extra ball. Buzzer for over the top.
There are a limited number of sounds available for EM's and buzzers or are not included in most games. I'd never want to remove one from a game that does have one.
Try some different 455's until you find a length you like, Maybe some tape or foam on the buzzer to quiet it a little. Or just enjoy it the way it is, because it was probably designed to sound like that.