An easy way is to boot your phone into the bootloader with the power and volume buttons, or by connecting your phone (need ADB enable in developer settings by tapping 7 times on build number) to a PC with a terminal running "adb reboot bootloader" (without quotes). If you have 52 in the version numbers, you have the Nougat version.
Thank you for the super speedy reply! I've recently updated to Nougat 7.0, and my bootloader is AO52 - so therefore I have what is being called the "N" bootloader here...?
Perhaps you can offer some advice to help me on my quest to divorce google... I'm aiming to install custom ROM without Gapps installed. I'm a newbie, but I've learned a lot about ADB/Fastboot/Autoflashtool/TWRP/Bootloaders over the course of the last couple weeks. I did successfully install the latest LineageOS 17, but it wouldn't recognize my SIM card. Some searching indicated this is common issue, and yet uncorrected... So I thought I'd try to roll back to an earlier version of Lineage that actually works.
Is this older 14.1 version what I'm after? I'm not a power user, just don't want big tech constantly scoping out my colon...