Investigated this. I'm not entirely sure that it's an easter egg, but it could be.
That looks more like a development error to me instead of a easter egg
As mentioned above, that kind of building is seen in military bases only so this place might have been a military base while the game was still developing but they dropped the idea of it being here and just forgot
But I won't rule out that this is an easter egg
An easter egg is a reference to something specific, or just something very unusual. I don't think it would be much of an easter egg, if they just decided to use an army-style wooden house.
It's just a wooden house. A very unusual one, but not an easter egg.
This place should be mentioned in Provincia de Don Velasco.