Not really sure if this was a thousands-of-hours job. Judging from the cheap polystyrene, fairly rough modeling and lack of things like wall modeling in the inside scenes, seems more like a hundreds-of-hours job.
Then again, it really depends on the age of this set. In the last 5 years it's really popular to make incredibly detailed polyurethane sets with 3d modeling and powderbed printing. Just the unpainted scenes only take a couple hours to make, the real handywork is in the painting, characters, etc. Also really depends on how experienced the people are (judging from the kind of store... probably extremely experienced).