Help me evaluate 20 Balboa / 1979 sterling @ 4 OZ sterling

[Argentium]

Greetings coin enthusiasts ! I just procured a 1979 proof , 20 Balboas sterling coin of the
republic of Panama - minted by the Franklin mint . It is in a presentation case with all the
attendant paperwork ie . certificate of authenticity etc. Any ideas as to value over melt ?

Thank You for your attention , Argentium.

 

[bocephus]

none

 

[Mackaydon]

I agree.