From what I can see, it's the .30cal and its pintle mount.... This is at least the fifth iteration of their M10.
I'm waiting for DML, HB or AFV Club to issue a correct hull and turret. Not Academy.
EDIT: Well well well! Ed Granger in this post
http://www.modelgeek.com/forums/227695&page=1says he spotted in the Hobby Easy post the following:
According to HobbyEasy:
"Feature :
1. New molded part of upper hull, turret, transmission cover etc
2. Cartograf decal and photo etched included
3. Reproduction of M10 “Early version" turret"
Now this has my attention!!!!