No evidence that lobotomies were used to treat gender dysphoria in the 1950's or 1960's. So to claim it was a standard treatment must be false.

The prevailing medical approach was psycotherapy, or reparative therapy, which tried to get people's gender aligned with their sex at birth.

Institutionalization is anyone's guess. People who did not conform with many different things considered "normal" were often seen as having a mental deficiency, and sometimes placed in institutions against their will even when it wasn't necessary. Standard practice, though? I couldn't find anything suggesting that anywhere.