That was the idea
But several of the rivets still turned out too massive - but for the purpose of 40k-ing the tanks, it works good enough. However, i'll try something different on the next tank. Still with rivets, but more effort (yes, THAT's what i need... do it even more complicated so it takes even longer. How many tanks do i need in the end? .... Should be done a few years after retirement).
Regarding uniformity... on first and second thought, i wanted to contradict. On third thought, i agree. You can explain everything with lore... but it all comes down to a business related decision by GW. But for Primaris, no other mark of armour is necessary - or would ebven make sense, since the other versions of armor accessible to normal marines are simply outdated models. But anyway... i am no fan of the whole primaris concept.
Custom designs, supported by a (credible) backstory are in defiance of GW's policy It's also fun to take your time and devise reasons why your plastic or cardboard tank is so different than expected.
Oh, i understood what you meant about the "making sense" aspect. Maybe i should point out that for me, it may be important in general - but it is also VERY dependant on the specific army. With my Dark Angels i stick - with a limited number of exceptions - stubbornly to the codex (that was valid at that time... i started with 3e...). So, it is again the narrative influencing the respective army.
So you see - it is not only what was intended by GW what makes my IG different from my Dark Angels. You could say they defy Mars as much as i do GW with them.