not to take credit away from Tim's idea, as the guys at Mezelmods do nice stuff but just trying to help - bounce a few ideas and then you run with the best.
This idea for you is keep the original post to maintain strength and then you can introduce an additional post that adds the custom colour, hides the wires, no de-soldering. It has a 0.35mm gap between the original post and the chute post and then a wall thickness of 1.25mm as strength is not an issue rather looks and wire hiding function is. The customer can dis-assemble their particular post, slide the wire chute post over the wires and then slide the wire chute post over the original metal post and then reassemble.
The wire chute post can have the cut outs for the wires to enter and exit top and bottom. This also means you don't have to tap the 3D printed chute - simply print, pack and send.
Downside is a little bigger than original post, but you can hide wires and colourise the post. Also just while posting realised that the visible groove where you can see the post could be rotated to the next flat so then you the player are not looking at the exposed groove and then post can be flipped 180 degrees as then depending on what ever side you can just see the nice post.
If happy can tweak the design and send you the stl
wire chute 1.png
wire chute 2.png
wire chute 3.png
wire chute 4.png