Irwin-Hodson in the USA had the contract to make plates for most of the UAE for the 1976 series. The plates were made in the US and shipped to the UAE ready for use. When Irwin-Hodson lost the contract to the Germans, there were three batches of plates still in the US that had never been shipped.
Known numbers are:
Ajman (AJ) 734-748 (2 of each)
Fujeirah (F) 15-28 (2 of each)
Umm Al-Qawain (A) 255-269 (2 of each)
It is absolutely confirmed that A was Umm Al Qawain.
These plates then found their way to collections. All are absolutely genuine but have never been near the UAE.