1998 Honda Civic LX--AC Compressor Clutch

I have a 1998 Honda Civic LX with app. 74,000 miles, recently purchased used from a private owner. I had the belts (including timing belt) replaced about 1 month ago, and shortly after began hearing a tapping sound when braking. The tapping would grow slower as the car decelerated. I brought it to the mechanic, who took it for a drive and called me back to say that he heard the tapping sound get very loud as he braked and then it stopped completely. According to him the AC compressor clutch actually broke off and was laying in the street behind the car. He said this can happen as part of normal wear and tear, and now says it will cost $1300 to replace the AC compressor, Receiving dryer, and condenser.

I am somewhat suspicious that this "broke off" when he was driving it, and now will cost $1300 to fix. Does this sound normal? Could it have anything to do with a problem caused during the belt replacements?

Thanks!