Hi Tim,
Sorry for your loss.
You mentioned that your father left you the gun so this Parker is pretty special. As Jerry said you have a DH grade that was a $100 gun back in the day circa 1890's. A big sum of money when the typical wage of a blacksmith was .27 cents an hour
The person you took this to knew what you really had and pretty much insulted you and your dad trying to get a big profit.
When you get the letter, let us know what the letter says. There could be some neat history of who and where the gun was ordered.