Collins KWM-1 Prototype

[kf5nzk]

I was wondering if I could get some help on valuation.
My father WA5ETV passed away and one of the key pieces of his collins collection
is a prototype KWM-1 with DC power supply and 516f-1 power supply.
I powered the unit up and it all works.
I'm not really into tube equipment myself so I really think this needs
to goto someone who will appreciate what it is.
I have done some research on what KWM-1 and accessories go for
but with this being a prototype and according to the research I have done there were not
that many prototypes made.
Any idea of what I should ask for it?
Thanks
KF5NZK
Marc