Hi Andrey
I am smallscaler, so I do not know the kit exactly. But I noticed some details at the box cover which do not match together: According to missing Zimmerit and muzzle brake the StuH was produced after 09/44 . At this period the gear wheel was without central thread for cover plate and the hatch stop was cancelled (flat hatch, when open). According to "Assault gun 3, backbone of the Infantry" , publish by Historyfacts, the fender support, made of pipe with add. steel triangle was attribute of MIAG production, but only Alkett built StuH. There should be a travel clamp also. Btw the towing bar at the back was introduced at 12/44.
Regards from Vienna/ Austria
Robert