I can understand this, because there were some new 105s hitting the streets without the other updates in the new year, and then in April the new dash etc. arrived, also with the new 105 engine. The 105s at the beginning of the year were transitional.
No no no no no no NO!
The 500 specs have always worked like THIS
Interior bits of trim colour, choice of paint colours, equipment (air con, blue&me, seat upholstery, choice of interior plastic colour) is dictated by the spec level - Lounge, Sport, S, Street, Blackjack, Twinair spec level, pop, cult, byDiesel, byGucci, GQ, Colour Therapy, Pink etc etc.
Engine, gearbox, suspension, brakes are dictated by the engine spec - 1.2, 1.4, 75bhp mjet, 95bhp mjet, 85bhp TA, 105bhp TA.
Fiat also do MY updates as well, such as the MY10 update which gave all Fiat 500's the stiffer rear beam and S&S. The changes made by Fiat in April would probably be classed as a MY type update.
The problem with information supplied by an idiot like this dealer is that if it's regurgitated on a forum then people treat it as fact, I challenge you to walk into any other dealer and talk about a Mk3 Fiat 500, they'll look at you like your head is spinning on its neck, it's completely nonsense and meaningless to anyone else other than the person who made it up.
The 105hp Twinair has ALWAYS come with disc brakes at the rear, that is part of the spec that the 105bhp brings to the car.
A different Mk of a car is almost always accompanied by changes in panels, lights and so on and so forth.
Let's take the Punto for example.
Mk1 (someone will probably be able to tell me whether this is a series 1 or 2 Punto, I'm guessing a series 2 by the clear indicators and the fact that it's a later one)
Mk2
and Mk2b
If you want to confuse and misinform people then feel free to continue using incorrect terms made up by some mouthbreather at your dealer, if you wish to provide people with good information then please stop calling your car a Mk2 or Mk3 500 because it is neither of these............