old french bass

[Nelson Cascais]

Hi

I´m thinking on buying an old french bass 1860. The seller says "it is just coming from the luthier for a complete restoration and it has had a fresh coat of red brown spirit varnish matching the original. This is just to protect it and is in line with keeping it as original as possible."

My question is: is it a normal procedure?
Does it afects the tone?
Does it have an impact on the value of the instrument?

Hope someone can help me with this questions...

Thanks
Greetings
Nelson