I have an old Berkley Models "Zilch X-pendable" and i am wondering how much it is worth. The kit is original and has all the parts with it. The balsa wood has been taken out of the sheets but the wood is still in great condition. I got the kit from my dad, who got it from an aunt who bought it from an auction in the 1970s. Apparently this specific kit is dated between the 50s and 60s. The box is in pretty rough condition and it has the original instruction sheet. I have heard numbers from 80$ to a couple thousand. Does anyone have any idea if it does hold some value?