I found this, of course, at an antique store. The celluloid of the cap and blind cap are gray/silver and black, and the barrel is gray/silver and clear. The nib is terrible, and after this pic I swapped it for a FPR flex. There is no branding anywhere, and I'd really love to know who made it so I could find some of their other pens. In my experience, cheap pens typically use lever fillers. So, this is an unusual one for me.
Oh, wow! It does look a lot like that. The cap is different, like you said. And the blind cap is longer on the Eversharp. That took me down a small rabbit hole to this Congress bulb filler! That looks even closer. The Congress looks like a knock-off of the Eversharp, and mine looks like a cheaper version of the Congress. I'm going to have to follow this lead some more.