Phil;
Thanks for the additional dope!
So... Apparently NO "factory install" on any new-production KV-2. OK.
So now we need to address those pictures in Peter's linked Beutepanzer page which show what I guess was a captured KV-2 in German service w/ Pz 17, with what looks like maybe 3 of these fuel boxes...
At what point do you think those boxes made it onto that KV-2? Would those have been boxes added by a Soviet repair shop before that KV-2 was captured, or maybe added by the German after it was captured? In the former case, I would suppose that the boxes were maybe installed at some rear-area maint center or repair center. If they were added post-capture by the Germans... where would they have got those boxes from?
In the above cases, it seems likely that those boxes would likely have traveled to some shop in some truck as spare parts for area shop installation (which goes with your info that apparently no new KV-2 received these as production-line fittings), OR they may have been scavenged from some KV-1 hull, either by a Sov repair crew or by the Germans furnishing their newly-captured giant... It's that, or they were delivered to some unit supply area or shop - where, with the 1941-42 German advances, they may have been captured?
Looking at those Beutepanzer pics... At least one shows what could have been the giant right after it was captured by Pz D 17 - with 3 boxes visible on its R fender - and before it was marked with balkankreuz. If that is the case, then this would suggest that the Russians had fitted those 3 boxes - and this fitting would have been to a later KV-2 during summer or fall 1941 in order to be captured with them on - which capture likely happened in summer or fall of 1941.
Given that these boxes didn't appear until JUNE 1941 or later, and most of the KV-2 were apparently destroyed pretty early on in 1941 or early 1942... There seems only a pretty narrow window of time that these boxes became available as spare or replacement parts AND made it onto KV-2.
Last but not least - You mention one KV-2 unit was repaired at LKZ in AUG 1941... What was "LKZ"? Was that some Sov repair center near to the eastward-shifting front?
Thanks again for all the dope and discussion!
Bob