can I get a watch that is not cellular but install cellular later?
The watches cannot be modified. If you mean use cellular on it then you are misunderstanding how it works. The GPS version only does not need cellular added to work with your device. The watch will not work without an iPhone.
There is no upgrading the Apple Watch hardware.
You can get the cellular and NOT activate cell service, then do it later. But you have to pay the initial higher purchase price to get the cellular hardware.
Note: if your iPhone is always with you, the Apple Watch will be able to make phone calls, send messages, get weather information, etc... using the iPhone’s cellular connection.
Apple Watch 4
