I recently gave $500 for a 28-2 which I did a couple of hours of work on cleaning to bring up to a 90-95% gun. It had tired wood grips on it. Your description really could use pictures and not mentioning the grip issue in your original post doesn't help in getting accurate value estimates. That said, While $550 may not be a steal, it's certainly not unreasonably high assuming your metal description is accurate. It would certainly bring that in my neighborhood and it doesn't sound like you will be paying shipping or tax which are two other factors.