Good-looking, well-dusted D!
Overall, you have done a great job here, IMHO. Other folks have ID'd a number of tiny fixes - and addressing them will add a bit of pop to a nice build. You could also add some dust to that small muffler on top of the big can... that's the early-style exhaust for the small aux motor used to rotate the turret, and dust would surely accumulate there as elsewhere. Also... unlike the main engine exhaust, that aux motor was a small engine which ran occasionally and that little exhaust probably did not "burn" nor rust near as much as did the main.
PS: AFV Bob mentioned those chains hanging on the smoke-bomb box... yes, they really look too big! The real chain was generally a very small wire-link item - it was connected to the box adjacent to each bomb-cylinder, and to the pull-ring on the bomb. The actual bomb, or canister, was the Nebelkerze 39-b, which is a can with a small pull-match inside and a pull-ring on top, and sometimes another larger ring or loop used to hang that bomb inside of the rack / box. The rack (one of 3 designs) was a box set up to drop these canisters so that gravity would do the "pull work". The chain pulled the ring and fuse and set the bomb alight as it dropped out of the box behind the tank. These bombs got very hot and posed a fire-hazard, and were dropped free of the moving tank (sometimes to the immediate dismay of closely-following troopies...).
Troops were issued the same canisters to be tossed by hand.
So... either the chains should be looped and attached to the bomb and to the edge of the cylinder (or a point close by on the under side of the box or its inner frame), or the chains can indeed dangle - but no bombs would be in that box in this case. You, and others (even myself) might consider adding a small ring with a tiny stick - the pull-ring and match - to the bottom of the dangling chain.
Here's how the box and bombs look - sketch-pic obtained from website and posted here for discussion purposes only.
Depending on the box-type, the box either tilted and dumped the bombs out (early boxes) or the bombs hung on hooks on a cam inside the top of the box (later) and were dropped when the cam turned. Both types released by cable from inside - or a trooper outside could pull the bomb out and set it off.
IF the crew dropped them, it was "all or nothing".
PS: I'm guilty of this leaving bombs in with chains a-dangle, too!
PS2: I THINK that the little brass "cups" included in some PE kits are actually meant to be the small base-cup the bomb stood in when it was inside of a box-type that tilted to drop bombs. But maybe NOT part of a box where bombs were hung on a cam w/ hooks?
Bob