How can I tell if I have the bootcamp windows drivers installed What things should I look for in Windows to determine whether I have the bootcamp drivers installed? Are there some files or registry settings I can check for?
The ‘Boot Camp drivers’ are two main things: Boot Camp Control Panel (for adjusting Mac-relevant Boot Camp settings) and drivers for hardware components. This is why Boot Camp refers to the ‘drivers’ as ‘support files’ because there's a little more than just drivers for Windows.

Windows 10 can automatically install a few of these hardware drivers, such as Bluetooth or Wi-Fi without the need to run their installers provided by Boot Camp (occasionally even newer versions are available outside of the Boot Camp drivers). Whilst these drivers are installed as part of the Boot Camp support files, identifying whether they are part of the Boot Camp drivers is an effort in futility.

The Boot Camp control panel can be found in the notification area if running, or in the Start Menu or Program Files folder. You can see if the software is installed in Programs and Features in Windows.

Without knowing why it's useful for you to know whether Boot Camp is installed, it's not really possible to say where to look, as there are too many independent components which make up the Boot Camp Windows support software.