A few things that may bring the price down, at least to a collector:
The stocks look like they don't fit right. Maybe someone else can say if they are K-Frame Stocks (the HP has the larger N-Frame).
The front sight has a red insert. I don't think this was a factory option back when yours was made so it was added later.
The trigger looks like it may have had a trigger shoe on it(?) at some point.
On the plus side, it does seem to have a much better than average finish. It's funny, some of these left the factory with a better polish and finish than others. My guess is that a really experience old pro did the polishing and finishing, and / or they had a light work load that day and it got extra attention.
Someone can correct me if I'm off base on any of this. It is worth every bit of $550.
They are K frame grips. Still very nice.
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