Pinky, there are two large pieces for the tarpaulin that is as large as the chassis itself, plus two smaller parts for details...
Hey, it was just a suggestion. I'm a WW2 AFV fan (in case that wasn't obvious), a consumer - and someone who wants to see Rubicon conquer the 1/56 scale AFV market. That's why I bother to post here (and that includes spending quite a lot of time checking facts). You guys are the kit designers, but you've asked for feedback, so that's what you get. And that includes suggesting ways to make your kits more attractive than Warlord's (e.g. by including a piece like the hood, which attracted a lot of positive feedback). And trying to help you avoid the inaccuracies that have marred some of your kits.
With that said, I don't know who your researchers are, but (as this thread demonstrates) they're still getting stuff wrong. I'd like to see you avoid the mistakes that can undermine your otherwise terrific models. Please take the comments below in that constructive spirit!
Stowage boxes - nice photos, although the third one is an M2, not an M3. The stowage
racks (not stowage boxes) were added to all versions of the half-track. There were different types of stowage
boxes on some of the special purpose half-tracks, such as the M4 (see below). The stowage boxes in your kit appear to be redundant.
Radio - your top photo appears to show a radio installed in an M2, not an M3. The bottom photo is a resin kit - I dunno what it's based on. I'm no expert on WW2 Allied radio equipment - it's a rather complex subject - but I think the radio in your photo is an SCR-528 (the same radio installed in US tanks but not normally in the personnel-carrier half-tracks). Or it might be an SCR-608, which was used by the artillery. I'm not sure which version the radio in your kit depicts, but I still question its inclusion.
Mortar carriages - as I originally pointed out, the mortar carrier version of the M3 was the M21, not the M4 (as your prototype was labeled). Only 110 M21s were built; they
all had forward-facing 81mm mortars, and about half of them were used by the Free French. Most of the mortar carriers used by the US Army were M4s (572 built) or M4A1s (600 built). All of these had rear-facing mortars, although some units (including 4th Armoured) re-positioned them to face forwards. The only real differences were that the M4A1 had a reinforced floor and mounts for firing from within the vehicle. There was no M21A1.
Your latest drawing shows a vehicle that didn't exist i.e. an M4 (although the ammo storage is different) built on an M3 hull. Here's a top view of the M21. Aside from the position of the mortar, the layout is quite different from your drawing.