I just looked at several pics of 25-15 examples on Google and it definitely looks as though S&W made them in highly polished and lesser polished variants. Obviously your example is a little of both.
Finish wise, it puts me in a mind of what a Model 28-2 Highway Patrolman barrel would look like on a Model 27-2 frame! (Aside from the caliber difference of course.)
If it is too much of a pain to return I would simply tell folks it was done intentionally to keep the glare to a minimum when shooting! (It is now a tacticool revolver

)
Just for giggles I would keep it just to show folks "Look what those goobers at S&W did!". I didn't see any other dull/bright combination guns when I quickly searched, but obviously at least one example is out there!
Here's a link to a duller finished example:
Smith & Wesson S&W Model 25-15 The 1955 Model .45 Target Heavy Barrel 150256, Blue 6 1/2" Double Action Revolver & Box, Mfd 2013 No Ca .45 Long Colt For Sale at GunAuction.com - 16495042
And here's a link to a more highly polished example:
https://www.rockislandauction.com/d...n-model-2515-double-action-revolver-with-case
Most assuredly they had varying degrees of finish with them.
Dale