Yes, but before those anti-wiretapping laws the phone company could theoretically do ad-hoc wiretapping of their own and voluntarily divulge that to the government. The only limit would have been that the phone company couldn't have wiretapped at the direct behest of the government since the Supreme Court had already ruled that the 4th Amendment applied [to the government] where the person had a reasonable expectation of privacy.

The statute fixed that privacy issue and then put requirements on when wiretaps could be used by the government. Before this law and the Supreme Court decision the government was very... lax regarding warrants for wiretaps.

http://www.it.ojp.gov/default.aspx?area=privacy&page=128...