Zip codes use was atarted in 1963.
Add this to strange facts
The current use of the po box 34567 is
Ashland Chemical Company, A Division of Ashland Oil, Incorporated P. O. Box 34567 Houston
http://216.239.39.104/search?q=cache:KYpWils0C3IJ:www.hd.co.harris.tx.us/pcd/ViolationNotices/1991HCPCDVNs.htm+Ashland+Oil,+Incorporated+34567&hl=en
The use of PO Box 34567 for Ashland Chemical was previously noted on this thread, and dates from 1991.
I looked it up on the USPS zip code finder page, and PO Box 34567 does NOT exist today. The address standardized to PO Box 24567, zip code 77229.
Strange indeed...