Maybe. Let's address this from two angles:
- Could an adapted person live without pressurization on Mars
- Would a person adapted to high level be able to need
significantly less pressurization.
Base data and tools
Could an adapted person live without pressurization on Mars?
No. The pressure at Mars sea level is 1.2% of the lowest pressure at which people on Earth have ever lived. Being adapted to Earth high altitude isn't going to help on Mars. Without pressurization, our high-altitude adapted person will die the same quick death on Mars as our sea-level adapted person.
Could an adapted person need less pressurization on Mars?
Yes, quite a bit less.
To pressurize a Mars habitat to Earth sea level needs a structure that can withstand a pressure difference of 100.7 kPa (101.3 kPa - 600 Pa).
To pressurize a Mars habitat to Earth's highest habitable altitude, 5100M, needs a structure that can withstand a pressure difference of 48.3 kPa (48.9 kPa - 600 Pa).
The structure that our adapted person needs must contain only half the differential pressure of the structure needed by someone who requires Earth sea-level pressurization. This could conceivably result in a lighter weight structure that is easier to build or transport.