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.
The body style bears some resemblance to the Eversharp Bantam at the very bottom of this page https://vintagepens.com/Eversharp_Bantams.shtml though not sure if the cap is right (and a low res picture)... And the bulb is different...
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.