I feel exactly the same way. It doesn't have to be tied up in a neat little bow.
Jango was originally going to have his armor painted the same colors as Boba, but when George saw the bare-metal look of the freshly cold-cast and polished plates during a test fitting, he liked it a lot and said to leave it like that.
In-universe, I've always felt that the armor was whatever was under the flight suit. A pressure/anti-g suit like what early astronauts wore, or what Fenn Shysa wore in his debut issue -- incidentally, while in a fight. Had his helmet on, had his gauntlets, had his belt and ammo pouches, had his cape and a jetpack. No flight suit or body armor. We know Star Wars has stuff like "armorweave" fabric. By my lights, what makes Mando armor so awesome is that it's like the Star Wars equivalent of a fremen stillsuit (from Dune). There are other manufacturers, but the stuff they make is the most advanced, efficient, lightweight, unhindering, whatever, one can get. Armorweave fabric, something like anti-ballistic gel, perhaps enclosed plate rinforcement at high-impact points like shoulders and knees... That's the Mandalorian armor. The flight suit keeps it from getting dirty or snagged on stuff. The flak vest is another layer of armorweave protection, as well as being a plate carrier. And then the familiar torso armor is just an outer, easily-replaceable ablative layer. The first line of defense.
The gauntlets are self-contained weapons/equipment platforms, easily swap-out-able for specific mission needs. Likewise the knees and jetpack are interchangeable, depending. To say nothing of accessories like sash, belt(s), sidearms, tools for pockets, utility pouches, cape/poncho, trophies, etc. The helmet is likely the piece of hard kit least likely to be replaced. This, to me, is a perfect in-universe explanation for why Boba's body armor is a different shade of green, with a different color of primer under it, than his helmet. His helmet is original-issue. The plates are replacements. Again in-universe, while the fitting and individualization of the armored pressure suit might be the equivalent of a small car in cost, the outer plates will never be that expensive (unless they're made of beskar and blah blah rarity and Mando smiths). Even with compact tractor beams and readouts of whatever systems the chest display is displaying, and possibly-exotic impact-absorbing padding materials lining them, those plates would never be more than maybe the equivalent of a couple thousand dollars, plug-n-play ready. Probably less.
My favorite, air-out-of-the-sails theory as to "the origin of the dent" is... Boba showed up on Concord Dawn a couple years after the Clone Wars ended and tried to live a normal life, signed up as a Protector, who were rebuilding their ranks after being wiped out almost to a man toward the end of the wars. I like to think that, when he completed his apprenticeship and made Journeyman, he was given one of the helmets of a Protector who had taken a bit of shrapnel in the head during the Clone Wars that had snapped his neck on impact. Y'know, tried on one then another until they found one that fit right. Luck of the draw, "inherited" from an unnamed, unlucky Mandalorian Protector who didn't duck fast enough. 
--Jonah
