I'm from Lithuania and I remember my father told me many times that our economy before sovietism was similar to the economy of Sweden but I cannot find any info about it. (Sorry for my clumsy English)
I'm from Lithuania too, and what I heard from my grandparents is that pre-soviet Lithuania indeed was more or less equal in population, available farming land and general development to Finland.
I don't know why you heard it was Sweden. Sweden was far more developed than Lithuania and had higher population.
It would be nice to dig up something concrete if I do, I will attach links to this comment.