Diana 36 Carbine, T05 trigger, .177 cal., stamped 11-02 on the reciever, perfect condition, comes with a BSA 3x12x40 scope on a 2 piece mount. Shoots 800+ with RWS Domes. What it's worth?

Of course only you can answer that question.36's are great guns.If the condition you described is accurate,with scope and mounts,I would place the value at approximately $175 to $200.There is always some risk in buying used unless you know the seller personally or have been able to examine the gun firsthand.

"The Almighty grants us rights, men restrict them".

ask if you can shoot it . If the chrony is available to use while testing ask for that too .Proof is always in the shooting . Even if it doesn't hit the claimed 8xx , if it's accurate and good shooting otherwise - it's a "buy it" .  Doesn't 'sound' like a bad deal gun wise - is it a best offer ? or is it priced ?