Cool section of Post Office Boxes

We found this section of 96 old post office boxes at a flea market near Tampa. We are using it as a table in our foyer. It appears to have been used as a mailbox at a trailer park for some time (it has names and lot numbers on the back) after being removed from the Post Office. The woman we got it from bought it at a garage sale 20 years ago. So, we are at least its fifth home. Based on the prices of individual doors on eBay, it seems we got a good deal. But, we are curious about value and approximate age. Thanks!