Value needed on an mg 34 stand behind tripod

[britrecko]

i am selling a TNW mg 34 in semi auto configuration.I sent to them an authentic nazi marked mg 34 parts kit and they did a very creditable legal conversion.
This was many years ago when they first started their services.
At some point i purchased a stand behind tripod with the tripod attachment fitted to the gun.It is similar to the anti aircraft mounted tripod. I cannot recall what i paid but it was not cheap. i may have purchased it from IMA.
I am selling the gun for what TNW charges now with its replica parts but i cannot find a reference for what a fair market charge is for the tripod and swivel mount on the top of the tripod.?