It's very hard to tell from the pic, but it may
have started life as a Bob Long Signature Series 2000 (note these are not 2000 spec cockers). If that's where it started, it's been modified further, they didn't come with anything chrome. It might just be a one-off custom that looks sort of like that generation BL/SS and has a Bob Long barrel.
Edit: after closer squinting, I don't think it is a BL/SS 2000, they didn't ever have the rounded/ramped sight rail as far as I'm aware. Every one I've seen had a totally square body. The centerfeed with the big square back block is what made me think Bob Long, as well as the barrel, everything else just doesn't look right. Hard to say for certain since there are quite a few variations floating around out there...
Here is a link to a pic of my BL so you can see the similarities and differences: