Dimmer Switch Isulation

I read this on Mustang 360 about a dimmer switch plastic insulation. Does this need to be done? Has anyone had this issue? Where would you find this insulation?

From Mustang 360: http://www.mustangandfords.com/how-...t-do-it-top-12-wiring-mistakes/photo-gallery/
Dimmer Switch Protection

There’s a reason Ford installed this plastic insulator between the dimmer switch and floor pan. If you don’t have one, please get one immediately. The dimmer switch is made of cast aluminum and your floor pan is steel, and touching dissimilar metal can cause corrosion. This is a region where moisture can get in, so the problem becomes even more critical. You don’t want a short to ground at the dimmer switch. This piece also properly routes switch wiring.


We see more dimmer switch installations void of this important insulator, which goes in between the dimmer switch and floorpan. Don’t forget to install yours.

Add to the equation a liberal sprinkling of H2O from your feet and the reason for dimmer switch failures really becomes evident...especially on the darkest night of the year, on the most deserted, windy stretch or highway, at speed, and when you press the dimmer and the lights go out....

.......you are in deep shit ?????????

Thanks for the advice.
Didn't know this isulation excist.