Found this on ebay and the design really speaks to me. Still, I'm not quite sure if it's real.
I'm going to guess it's a mod; assembled from aftermarket parts. It kinda looks like it, and the caseback doesn't say seiko. Care to share the listing?
Edit: closest I could find is this:
https://marketplace.watchcharts.com/listing/16851459-seiko-mod-5-sport-1880a-black-automatic-luminous-hands-indexes-men
There's a while community for building modded seikos.