It's usually not a good idea to force games to render in widescreen when they didn't originally support it.
Hell, even in Widescreen, a lot of Oxbox games have weird quirks. Halo 2, for example, doesn't render water on the left side of the screen (including multiplayer) because it assumes it'll be behind a bezel, even though it supports widescreen. Now imagine doing that to a game assuming it's in 4:3, and as the Prime video shows, that will likely happen with Conker. Messed up rendering.
It's also to be considered that these games are also LAN capable with the original Xbox itself and 360s emulating it, so you don't want to go breaking the game for that either.
The N64 didn't even have component output. It did not support widescreen, outside of game occasionally adding black bars themselves to the top and bottom of the picture for effect.
In other words, this is just not true.
Amusingly, Rare DID support anamorphic widescreen in a bunch of their later N64 games - except for Conker. They were the only developer to actually support it on the N64, though.
Conker was also weird as it was also a late stage N64 game by Rare that made no use of the expansion pak.