Great score in my opinion! I just recently have discovered the joy in collecting postcards! You get a stamp, a picture, a glimpse into someones life with a story, a cancellation and usually a notation printed about the subject matter. It's just a pothole back in time. I especially love the first one of the Flat-Iron building. There was a saying in the late 20's to mid 50's "23 skidoo" (I probably spelled that wrong) but it was thought to have originated around that building. I guess the wind in the city would really build a head of steam and blow up ladies dresses and so the men, not surprisingly, used to loiter to watch the spectacle, which would have been a big deal morally back then and the walking street patrol AKA: the police would tell them to ski-daddle or to skidoo! (basically to just move along)- so the reference was made to do the old 23 skidoo!
It was actually the first and fastest "hip" saying to sweep the nation and has been spoken in many movies and even cartoons of the day! Most notably, in my mind anyway, was Popeye the sailor man. Olive oyle was known to say it. I just yesterday watched that episode so that's why I remembered this!
Here is some information on it for your amusement-