I don't even use a mounting bracket.  The housing is plastic and I
"pressed" it in the hole after (like I said) a few swipes with a
file.  Didn't take much and the thing fits so tight I hope it lasts
for a long time..  Mine has a black plastic bezel and doesn't match
anything but the price was right.  It was in a discount bin at the
local FLAPS; opened box but not out of the plastic.  Been in there now
for about six or so years.  I can send you a pic if you want.
Studebaker George