As stated like 1m times over the forum by many, domain is worth what the buyer is willing to pay for.
If the buyer is obsessed with the domain and he has deep pockets, the skies are the limit.
I personally think it is not worth $800k, but more like low-mid $x,xxx for end user.
The "1st" addition is bad for the domain.
And yes, it is possible but rare that no one is actually notice an high value domain name of 6 figures value which is about to drop.