> any Baal Tseuvah is probably safek goy.
probably true more of Americans than Soviets. Americans are intermarrying for quite some time and may have crossed the ocean 100 years ago with loss of papers and archives. Those who stayed in USSR and came to Israel in 1990s, there are 2 generations of assimilation, grandparents were probably still alive. If they hide or forge papers, then, of course, all bets are off.