I have the Academy Duckbill kit, its still in the box but it has a full interior, including the engine
theres a review of the M10 duckbill here
http://www.perthmilitarymodelling.com/reviews/vehicles/academy/acd1397.htm
and the AFV Clubs here
http://www.jbwholesalers.com.au/reviews/afvclub/afv35024.htm