Well duh. Touché my friend. It is indeed there. Like a dummy, I was following Roku's instructions to find the model and from there to find what version software version it's running. I got bogged down with that and never even thought to check the device itself.
My Roku Express+ 3910X unit is serial YG00AM712707.
For televisions, which work different than the actual Roku's themselves, the serial number can be found in two places.
The serial number can be found on the back of the television, in the center, at the very bottom.
It can also be in the menu, under "About"
I lost the TV stand legs and I’m trying to get replacements but i can’t make sense of the model numbers, mine isn’t anywhere. I’m very confused.
Model number: 8207X
Serial Number: YK00NW513881