A little high on price, perhaps, but who cares so long as you're happy? All of us who collect have at least once paid a touch more than we ought to have for a piece -- but here's the save: tell yourself you paid fair market price, just a year or two early.
What's also worth taking into consideration is if the item is as you described, a true 99% or better Model 13 inside and out, with all factory accoutrements like the box, papers and tools -- that's a collector's level package and does command a premium. If that, the price is closer to reasonable.
And yet another way of looking at it: a comparable new S&W would cost as much or more, and you'd have the internal lock, a perhaps lesser build, MIM internals, and zero current collectibility.
Instead, for the same price, you have essentially if not actually a new S&W, no longer made, in an excellent, desirable platform, from a time when build quality is thought to have been better.
The Model 13 can alternately be called a .357 Magnum sibling of the Model 10 heavy barrel, or a fixed sight, heavy barreled sibling of the Model 19. Same either way.
It's an excellent fighting gun. P&R (pinned and recessed) refers to the pin that secures the barrel to the frame, a feature S&W did away with around '82; and the cartridge recesses in the cylinder that are a throwback to when .357 ammo was more likely to rupture on ignition -- the recessed cylinder allowed the cartridge to sit farther in, offering the gun and the shooter better protection in the event of a rupture.
The pin is considered desirable for better seating of the barrel, though it might be unnecessary; the recessed cylinder ceased to be needed once better .357 ammo build quality came to the fore.
P&R is considered representative of a superior time in S&W craftsmanship -- though that can be debated -- but is why a "P&R" gun is more sought after.
Might to consider an alternate piece for carry if this one's truly collector grade -- in leather that finish won't stay pristine. But do enjoy shooting it at least a little -- you can shoot and maintain a gun's great condition with some conscientiousness and care.
Or heck, call it yours and ride it hard -- what matters is it sounds like you got a great revolver. Enjoy.