No, "there is" can sometimes translate to "det är", but "it is" can never be "det finns". You can say "det finns röd färg på insidan" but that means "there is red paint on the inside".
When you say "det" we assume you're talking about an ett word. Therefore, "röd" would need to take the ett form to match up with "det", so the sentence would be "Det är rött på insidan".
Hope this helps!