The 150 T-jet has lower compression, so no its not just a "map"
Car manufacturers now always develop cars correctly for long term durability, they can't afford there reputations to become tarnished by the ever increasing reliability we as the buying public demand, even cars now that are deemed to be unreliable would have been the epitome of reliability 20years ago.
The compression ratio is lower, how they do this on this particular engine, I don't know, most likely different pistons, the 150 also has a bigger turbo as well. the reason for this is modern cars are mapped to give very flat torque curves, this makes them drivable and have none of the torque steer that used to be associated with turbo cars, therefore for a given amount fo power a turbo is specified for that application, so the 120 turbo is very small, this helps spool up time and keeps good fuel economy.
It is likely that yes you could get some useful gains from remapping, but at what cost in terms of reliability is unknown yet, engines too new.
You can take the VAG 1.8L 20V as an example it came in 150 and 180bhp guises with 9.6:1 compression ratio, but the higher output models the 210/225 etc were 8.6:1 and some other modifications like, stronger rods pistons and different turbo, yes you can remap the lower models higher but they will never last as well as the properly specified engines.