I would make the 100 mile trip ( hopefully have something else to do in the area ) ...and inspect it closely / and still probably pass on it.
I assume you mean if its reblued. A reblue obviously kills the value BUT dare I say, its still a pretty good deal if reblued. A factory reblue may have letters such as "R-S" or "R-B" sometimes inside of a box on the left grip frame if factory reblued. It also could potentially have a date stamp such as "3.75" meaning March, 1975, on the left grip frame. At $450 for gun, box and holster, when the box is probably worth $100, means you are in a "reblued" (if it is) model 27 for only $350. I'd say that's a deal just for the utility value of a model 27.
Hard to judge by that picture. One thing that stands out to me is the front sight with orange insert. I'm no expert on all things S&W but that sixgun should have a black patridge front sight. This would be a deal killer for me unless the rest of the gun was pristine.
I was under the impression that 28's only came in 4" and 6" lengths and only with the black ramp front sight but my memory may be failing. There's a possibility that the red ramp is original but it's doubtful. I've never seen one with a red ramp but I've seen a lot of guns that came with something else but were modified with a red insert.
You are right about model 28s that they had standard a black ramp, 4 or 6in barrels but there was a special run of 5in barrels made. I wonder if someone could have ordered one with a red ramp or not. As far as it being a deal killer, it really doesn't the lower the value any significant amount in the retail setting, but I can see to you, and to others, it would take away the interest.
Model 27s at that time (I assume the OPs gun to be 1970s) were available with any sight combination, since they were a deluxe model. Of course a ramp on an 8 3/8 barrel is unusual, but it could have easily been requested from the factory, along with the red insert. Its kind of like having a 4in 27 with a patridge target sight. While unusual, it was in fact a factory option. So possible, however improbable.
I bought a letter on my Xmas present last year from my wife, a 1951 357 magnum, pre model 27. The gun sports a ramp with red insert. Here is what Roy Jinks personally said of this matter:
Here is the gun, one of my favorites. I would say mine did not come originally with the red insert, but those inserts became much more common later. I believe my ramp to be an original sight.