I apologise for writing in English, but unfortunately I don't speak Hungarian. Anyway, I am aware that Malév operated cargo flights using Il-18's and, later, Tu-154's(which in itself is interesting, cause neither type seems to have had cargo doors installed).  But, I did recently stumble upon a picture which made me wonder, did they ever operate cargo flights with Tu-134's?

https://russianplanes.net/id41529

This is the only photo I have been able to find of the aircraft, HA-LBE, between 1985 and 1996, when it seems to have gone to the Aeropark, and as you can see, the windows are blocked. I will admit, Russianplanes does also state that the aircraft last flew in 1987, and there is no mention of it being converted for cargo use. But there's no mention of HA-LCA being converted either, but as we can see here it did operate cargo flights.