Help With These Belgium Proofs? That Appear To Have Be Been Postal Used.

Found these Belgium stamps in a lot of kilo that appear to be maybe proofs or specimens but I thought those had overprint identifying them. They are about the thickness of heavy paper, on very stiff stock almost wood like, are imperf, have been glued to the cover material, from what little I can see there is nothing on the back and none of them are listed in Scott as issued varieties but they appear to have been used as postage. Is this someone playing around, another post office oversight or something else? I have read that dignitaries are issued imperf stamps but I assume they are varieties released for sale. There is a full set of released King Albert with this design but the colors and denominations don't match these although there seems to be these colors in other denominations. I find nothing close to the other two designs (owl and farmer) cataloged. I thought about pre printed stationary or card cutouts but I have never seen anything like that printed on this stiff stock.

This is all that was left of the cover and it didn't tell anything. Postmark is "GENT" (but web search spells it Ghent) and the date appears to be 20?? 20 7. The approved Albert issues were released in the 90's. Searching has been unsuccessful. Can anyone clarify?

Web search on American sites!

The town is called Gent, not Ghent.

The owl is a cutout from postal stationery, Briefkaart. I'm going to assume without further checking that the kings are postal stationery cutouts, as well.

I have been looking for information on the validity of cut-squares for postage. Unfortunately, I have not found any confirmation on it.

Stamps with BEF values remain valid until 31-12-2027. I have a suspicion cut-outs are considered stamps.

I search on my iPhone & Wikipedia had it spelled that way. Didn't know I could search any other way. I occasionally get foreign language responses but I just skip over them. My comment was only informational not intended to imply anything.

What is the print stock used that is so stiff? I have never ran into any post cards printed on anything but poster board/cardboard type material.

I do thank and appreciate your responses.

Gent in Dutch, Ghent in English (or Gaunt, as in Shakespeare's John of Gaunt). And a lovely place.