Will Android be able to install OS updates without Google account? I am working with android phones at work, we want to remove all google accounts from the phones before we give it to our customers. 

I know that the phones are not able to receive app updates, but what about os update from android?
OS updates are provided by the device manufacturer. They are retrieved directly by the device and don't require any user account.

The only requirement for an OS update is a working Internet connection and enough free space on the device.