Unef1 Covers - Missing Dates

In 1956, in the aftermath of Suez and Arab-Israeli fighting in the Gaza Strip, the United Nations created their first Emergency Force and sent it to Egypt in a peacekeeping role. Amongst this force was a detachment (Odred) of the Yugoslav People's Army (JNA), and Yugoslav soldiers remained with the force (Egipat) until it was finally stood down in 1967.

JNA soldiers were entitled to free mail. All they needed was to have an envelope officially handstamped Postarina Placena Pausalno (which roughly translates as 'inclusive of postal charges'). Alternatively they could use official UNEF stationery; though these don't seem to have been much used by the Yugoslavs, probably because all the instructions on them were in English. (Both these are shown in the first scan below).

Now we get to the nub of my question. From 1957 onwards they had a third alternative, in the form of special 'commemorative' envelopes produced by the Yugoslav publishers Jugofilatelia in Belgrade, who amongst other things produced stamp catalogues. These envelopes can be found genuinely used, but the majority were probably just sold off to collectors, cancelled but not addressed. (I suspect that only the 1957 cover below is genuinely used. I doubt whether many of Mr Samotorcan's friends took a typewriter and set of labels to war with them!)

I assume these were issued every year. But as you will see below I have yet to see issues for 1962, 1964 and 1966. I would very much like to be certain that these exist, and also to see what they look like. Can anyone provide scans?

As William Empson (almost) said:
It is the covers we have lost,
The ills from missing dates,
At which the heart expires.

Less than a week since I put this thread up, and this afternoon I'm sitting here idly scanning through innumerable auction lots hoping to find some Italian-Croat bilingual cancels (OK, so what do you lot do with YOUR holidays then?) and there I am, staring at the 64 and 66!
Still no sign of the 62, though.

I have just found an article on these in the 1981 Journal of the Arbeitsgemeinschaft Jugoslawien. It DOES NOT list a cover for 1962. I would take this a pretty firm evidence that it does not exist, were it not for the fact that they also do not list 1965 and, as illustrated above, I've got a 1965!

Nevertheless it is clear that if the 1962 ever existed it was at least scarce even 30 years ago.

May I repeat my request for anyone who has one, or knows for certain whether it exists or not, to comment here?

As this is in the wrong forum (has nothing to do with Canadian stamps or covers), perhaps moving it to the "World Covers," forum or the "Main Stamp Collecting Forum" would generate some replies as there will be a much larger audience.