Most apartments in Montevideo don't apply for BPS even if it's a major renovation. Why? 2 reasons. First, although there is always a trash box sitting on the street for rubble, I've never of a BPS inspector following one up. Second, apartment renovations don't involve changes to the physical plan (or usually don't).
The point is that if the renovation isn't visible from the outside or doesn't involve a change to the building plans, no one applies for BPS.
In theory, an employee could rat you (the architect or GC) out to the BPS but they usually want to keep their jobs. They're not terribly worried about a reduced or no pension when they're old and cant work any more.
If there is no record with the BPS of the condition (wall colors/materials) of the house from the past; if the renovation didn't remove/add walls and if the renovation didn't involve a change to the outside of the house (even the color of the paint), there's nothing to worry about. It wont register on their radar.
About the wall color, my neighbor was fined by the BPS for not taking out a permit when she painted the outside of her house.
This advice applies to Montevideo only. Once you're outside the big city, it's rare to take out a BPS permit unless it''s on the path the inspector takes from home to work or the local boliche.




