Using the new apple watch with cellular without...

If I don't initally activate the cellular will the watch still work as a series one currently works and allow me to make and take calls on my iPhone?

Yes - Apple Watch Series 3 (GPS + Cellular) can be paired, set up and used for other features after skipping activating the cellular feature during setup.

The cellular feature can be enabled later, if and when you are using a compatible service plan on your iPhone.