An Envelope From Argentina To Former Yugoslavia Sent In 1951.

Is there anyone on the forum who collects envelopes from Argentina?
I do not know which route to travel this envelope but the destination is Zagreb (former Yugoslavia).
I am interested in more information on the envelope and postage stamp in the picture below.
As I see it, one stamp missing from the envelope.
Likewise, I am interested in the edge envelope. The edge of the envelope of aviation letter are not evenly distributed.
The envelope is closed and I do not dare open it (that I do not damage it)?
Is it worth to even pay attention to this envelope?

It seems originated on November/December 1951 from the Argentinan city of Comodoro Rivadavia. As far as I know, there were a number of Croatian people in Argentina. May be refugees from the WWII? The postage stamp, doesn't seem to be specially important.

Hi @Cursus
I just assumed it. But I'm interested in more envelopes and postal stamps. I will not even open it.
Nothing then, I'll put it somewhere on the bottom of the box and let it stand there.
Best regards

The backflap does not appear to be opened and resealed. I can only guess that the edge you are concerned about has been cut open by scissors or knife to remove its letter. I suggest you examine this cover more closely and see if that is true.

This is/was a privately printed envelope sold commercially. While this might be an interesting looking piece without all the damage, there is no real value or much interest in just the envelope by itself.

Hi @hy-brasil
Yeah, you're right. The edge is glued with so that they do not notice that the envelope opened
Best regards

Given the number of Croat war criminals - notably Paveli#263; - who escaped to Argentina with the help of the Roman Catholic church, I imagine that the Yugoslavian authorities would have opened mail originating there.

Hi @GeoffHa
I was not born then, so I can not comment.
Basically, as @hy-brasil has said, there is a possibility that the envelope is cut off with scissors, on the side I marked with the arrows.
Best regards