I'm done with this one - I forgot to paint and add the coaxial .50 cal, so assume the barrel is internal.
The articulation point between the two tanks (and where the exhausts would be - I assume - since I didn't add any) would probably be an RPG magnet, so I added a shield in the form of Tamiya tape with some tulle cloth stuck to it, then painted:
The anti-reflection coatings on the two imagers/targeting pods on the turret are Tamiya interference material. The coatings on the viewports are just clear red over Molotow chrome:
Our French mechanic friend is pleased that the RPG shield is not pulled taut even when the two bodies are at their maximum deflection:
Thanks for all the comments!