Is there any difference in meaning in the past passive voice used with or without "был"?
Москва основана в 1147 году.
Москва была основана в 1147 году.
Is there any difference in meaning in the past passive voice used with or without "был"?
Москва основана в 1147 году.
Москва была основана в 1147 году.
Of course. There is no difference in your case, however, the variant without "был" refers to the present state. Nowadays you cannot say "Советский Союз образован в 1922" because Soviet Union does not exist anymore. Moscow does, so you can use both.
The easiest analogy is as follows: