Pentax MX damping strip

Hi,
I am a great fan of the Asahi Pentax MX. Since a few weeks I refreshed the light-protecting strips and the damping strip. But I used a conventional PVC-dumping material made in the United States. It is stronger an a little bit higher (it is 3mm high) than the original. But there are no Problems with shadows from the mirror. But I think the MX sounds very loud an hard. Is it okay?
How many MX were buildt?

with best regards

I understand MX production started out at 15,000 units per month, but I guess it increased considerably beyond that.