Anything less than $500 would be very fair if it's unfired.
They are worth much more than a new Uberti.
PLEASE PLEASE PLEASE do not shoot it.
If you want a Centare to shoot, I'll be happy to trade you a REALLY nice shooter and some cash for an unshot one to be a safe queen. You will take $200 off of the value the first time you load it. Do posterity a favor and let that one stay as-is. PM if you want to wrangle.