No, they had no ads for several years. AdWords were introduced in 02000, at which point Google had existed (initially as google.stanford.edu) for four years, since 01996, which was 40% of the amount of time the Web had even existed. I started using Google in probably 01998, when people on Slashdot got excited about how much better their search quality was than AltaVista, but it probably wasn't until 01999 that I switched over completely—at first AltaVista still had better coverage.

Why the leading zeros on year numbers?