Seems you can find Parker Reproduction 20's in the $4-5000 range fairly easily, and except for the occasional lug failure they are touted to be better for extended shooting than their 100 year old counterparts. Point being, anything over that price and you are paying for collectibility rather than shootability. I went down the 16 ga road 30 years ago because I felt the 20's were overpriced and harder to find. Several of my 16s weigh just over 6 lbs with 28 and 30 inch barrels, whether on a 0 frame or a 1 frame, and I suspect those give a 20 gauge an even run for handling qualities. I have not paid more than $2200 for any of them, some much less. I have also acquired a Sterlingworth 20 with 28's, a Flues 20 with 30's, and an LC Smith Field Grade 20 with 28's. The Smith seems to feel more balanced than the other two at 6lbs 2oz. Again, not more than $2000 paid for any of them and only $900 for the Ithaca. The most I ever paid for a Parker was $5800 for a 28 ga VH with 28 inch bbls on an 0 frame. Weighed 6 lbs even. I loved that gun, but always took my 16's out hunting because I wasnt confident enough in my shooting to go with the small bore. Thats just me. I sold the gun for what I paid for it because I just wasnt using it. By the way, these are all 10%-20% CC guns with between 70% and 90 % bluing, and stocks without major issues and reasonably good checkering. This is a long-winded way of saying I think $8000 is way too much for the gun you describe, unless the gun is in benchmark condition, CC included. JMHO and good luck with the search.
Mike