Q for Anderson Ultimate 2 GN owners ...

[Centex]

... I'm curious to know the cross-section dimension of the coupler tube that fits over the gooseneck ball in the truck bed; I wrote to Andersen but they were not forthcoming with that particular info (?).

Referring to the piece in this pic:


Obviously larger than the 2-5/16" ball it slips over, mainly curious if it's larger than 3" x 3" ?

It's aluminum, too, correct? Threads cut directly in the aluminum bar-stock to receive the main 'tighten-down' bolt in the top?

Thanks in advance for taking the time to grab and share the measurement!