I think its luck of the draw. Romania was a small, poor communist nation. They had low production of many wespons, most likely, they rebuilt worn rifles over and over. Not having many to begin with, increases the likely hood of mismatched parts when rebuilt, they might strip one rifle to fix five rifles. The quanity wasn't there to choose from like China. Look at all the Romanian capture/refurb Mausers, not many match, same with M44 Mosins. Just another though, maybe they didn't give two squirts about the numbers, the numbers don't effect function, maybe they were more function an and total inventory based. Them numbers weren't gonna win the Cold War, thats the guy weilding the rifles job. Numbers are over rated anyway.
In my 4 Romanian examples, its all over the place with numbers and condition. My 1957 is almost perfect, every number matches, while another looks rode hard and put up wet, it has a mismatched number or two, and one that I would say is pretty decent, but serial suffixs cover all 4 years of.production. And then one that again, ain't in horrible.shape, has couple of numbers match, but packs a Yugoslavian bolt.