These were smuggled ones from Ukraine when USSR collapsed. Things you could get from there at that time

. I think Croatia smuggled 40 MIG21's on trucks through Romania and Hungary in 1993. Also, in case of Mi8, they were different than MI8 that ex-Yugoslavia was using and than Serbia flew after collapse (those were much better). The fit and finish was horrible, some gauges were placed in different spots. For us was not a problem because we had 4, so everyone knew how certain helicopter operates, when it operated. But one begs the question about their operability during USSR and how all that functioned.
Sometimes later, way later after I left the country, Bosnian air force sent newer models, including MI17 that were acquired from Russia as part of debt settlement from 70's and 80's to Ukraine for upgrades. They got back worse helicopters than they sent. They have kept fuel tanks dry, which cause almost disaster etc. etc.