Winplumber, you're right. I grabbed a G grade that wasn't buried in the safe with the rest of the Parkers and stared at the top rib under a bright light. The line on the edges of the sighting rib is so faint that I could barely see it, but it is there. I could not see it at all under the rib matting. I'd never noticed it before on any of my Parkers or any of the photographed Parkers that I've stared at over the years. The seam on this gun's rib stands out in stark contrast and caught my eye immediately. Perhaps its a result of the rebluing? But I've seen plenty of reblued Parkers that didn't show the seam so clearly, so...
Since the heir asked, what's the consensus on the fair market value of this 12 gauge D grade with reblued barrels and extractors....maybe in that $2,500-$3,000 range in today's economy?

Jent the third picture down on the original post shows the rib inscription, Titanic Steel.

Book has it right Ti3 I dont think anyone with us can answer why / how the barrels were redone

Steve, has a vent hole been drilled in the bottom rib just forward of the forend lug?

Chilled-

No no vent hole that is obvious. The bottom rib looks continuous.

Steve

That's a good thing in my opinion.

Chilled - ?

Chilled-

What does lack of a vent hole indicate?

Steve

It usually indicates that a great deal of care was taken not to alter the gun from its original state. Parker Bros. did not drill a vent hole when they "rebrowned" a set of barrels and I think it detracts from an otherwise nice Parker.