Fuel Injector Insulator

[gt_me_jon]

I am new here and have searched the forums and could only find two threads that dealt with this item, and neither seemed to have any definitive conclusions. I have a 94 Ranger Splash with a 4.0 and I had to replace the lower intake manifold gasket and a leaky fuel injector o-ring. As I pulled the fuel rail and injectors off of the lower intake manifold, a couple black rubber gasket looking rings stuck to the lower intake manifold and tore. I am not sure exactly what purpose they have, but the dealer said they are "insulators" and insists they were only used on the Aerostar 4.0. I'd hate to put everything back together only to find out these were necessary. Can I just ditch them and only use the actual o-rings on the injector or do I need these "insulators"? Does anybody have any experience with this? I have linked the two threads referring to these insulators below in addition to including a picture.

http://www.explorerforum.com/forums/showthread.php?t=154213&highlight=injector+insulator

http://www.explorerforum.com/forums/showthread.php?t=106980&highlight=injector+insulator