Dynaco parts for a PAT-5

Not sure if this is where to post this or not, however thought I would start here.
 I just acquired a treasure trove of vintage audio and several of the pieces are "70s" Dynaco. I am starting to restore some of this gear and have run into a snag. One of the PAT-5 pre-amps is missing the black plastic pushbutton cover.
 I have searched high and low and have not been able to find a replacement.
 Anyone have any ideas?,
Thanks for you help and advice