Yes they were. Ecclesiatics is skeptical about a ressurection too.
For that matter, in the first 39 books of the tanakh, resurrection was only hinted at 3 times.. Two of those references are in Isaiah, and one is at the end of the book of Daniel. Altought Eziekel does mention it, it is meant metaphorically. Resurrection is not mentioned at all in the Torah, so it is a later introduction in to the Jewish religion, rather than an older one.
The Sadducees were actually representing the conservative, orthodox thought on that. The concept probably came into Judaism via Persia, and the Zorasterians