Bob,
At one time, a woman who married a citizen automatically became a citizen. Also, a woman citizen who married a non-citizen automatically lost her citizenship. The law has changed; citizenship is no longer automatically gained or lost through marriage. If your mother married your father when women automatically acquired citizenship by marriage to (male) citizens, then she was a citizen.
At all times, there were records that had spelling mistakes and there were name changes. At some times, there were records that don't survive for various reasons or can't be found easily. You cannot conclude that someone was not a naturalized citizen merely because you have not found a record of it.
In summary,
Can I conclude that she was not a citizen? No
Were the laws different then? Yes
Stephen Weinstein
Camarillo, CA
