I will be help. What is the size and at your convenience, please send images.
Can you see evidence of silkscreen printing, which would show seam lines between the colors, or are all of the colors flat and seamless on the surface? If original, this World's Fair design illustrated by Weimer Pursell and published by Neely sells for $450 - $650 at auction. This is however a popular image and is reprinted by online poster sellers and decorative wall art publishers. A reprint sells for $25 - $40.
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From the images here, these appear to be a reprints.
When reprinted, the image of the seams would certainly show, however there is not degree of layers on this that would be on an original silkscreen printing. If out of the frame, there is a distinct chalky type of feel and a very subtle feel to the layers also.
The chalky feel is indicative of a screenprint, and if you can feel that light difference in layer of each color then that too means it is a screenprint. From your observations, this is pointing to being an original. You may want to contact Chisholm Larsson posters in NYC to see if they would like to purchase this from you. Here is a link to their site for you: https://www.chisholm-poster.com/