Rifle "grading"

[Guest2.14.06]

Hi all, I am interested in selling my used FWB 300S, but am not sure what condition it is in.

The man I purchased the gun from sold it to me at 90+% for both blueing and wood, and I have kept the gun in my basement for the two years I have had it.

What are the parameters of judging a gun? Presumably, the gun is in the same rating as it was when I bought it, but I just want to be sure.

Also, how much does a FWB 300S at around 90% bring in?

Thanks in advance everyone, for your help.