The Tristar kit is a very nice item in many ways. I reviewed it a few years back. In actuality, the Tristar "munischlepper 1A" kit has the complete Pz.1A early/late kit with all of the interior including the engine compartment, plus an extra hull-top to provide for that open-top-w-cover arrangement, AND a very neat ammo trailer (which I sadly gamolluxed-up in my review...
In terms of building the munischlepper... You should consider carefully which of the interior bits would likely have been left in and which not - for example, I doubt that the un-armed munischlepper had full MG-15 mag-racks (the only such racks in the kit)... And there is no sort of ammo-storage for payload provided inside the hull - although the trailer IS complete in almost every way.
And, IMHO, the added specialhull-top is not quite as crisply-molded as is the original Pz. 1A hull top in the Tristar kit (I don't know about the HobbyBoss copy...), so I would consider working the original hull-top for better detail.
So - you can build the 1A with all interior, or a munischlepper, and have all the turret stuff for other uses.
Cheers! Bob :-)