Construction style of these sorts of NYC interwar buildings?

I've all the time thought the 6 story interwar elevator constructing in NYC was constructed solely of load bearing masonry, like the way in which brownstones or tenements are (with metal and/or concrete being reserved for fireproof buildings). However a buddy of mine shared pictures of his 1937 condominium constructing after being gutted, and there are clearly many metal (or iron) beams inside which are unique to the buildings. This isn’t that constructing, however a separate constructing that can be Artwork Deco styled and constructed the identical 12 months.

Be aware that the Division of Buildings stories nonetheless think about these to be "load bearing masonry", so I'm questioning if many Thirties buildings are literally hybrids of some type. This does make sense to me as a result of these buildings might be fairly giant, to the purpose the place being constructed totally of bricks and wooden doesn't appear all that possible.

Extra perception on this from NYC structure nerds could be tremendously appreciated.