Just noticed this today putting together joycons. The attached one was from a new pair of neon yellow joycons I bought from Walmart a couple days ago. The unattached stick is from an older pair of joycons. Both OEM nintendo.
I don't know if anything inside the actual stick/housing is different, but the outside clearly is.

I don't know if anything inside the actual stick/housing is different, but the outside clearly is.
