you really think so...the fabric on the door already would soak up the resin and then turn hard...if you wanna go all out then bondo that resined panel and sand prime and paint....you dont need to use chop mat or woven fabric to get a glass finsh...your woven fabric here would be the panel material....much like on a speaker box when you stretch fleece over the baffle...fleece isnt fiberglass either but if you bondo it then what do you know it looks exactly the same...you can apply resin to ANYTHING that it will soak into(wood, fleece, fiberglass, CF, kevlar, carpet

, jeans

, hair

) ...all the mat and cloth do are give it strength...its a door panel though it already has strength.
sorry tropiccougar i did read your post and i thought you said to remove the fabric on the panel and then glass over the foamy stuff...resin will eat that foamy stuff though and you could end up with quite the mess.
and just for a point it is better to stretch your fabric then apply mat or fiberglass cloth to the inside of your box. that way you dont have to worry about overlap lines and stuff and there will only be half the sanding to do as well..