Would a 1905 Liberty Double Eagle follow the bullion value, or more of a numismatic value? Would it be a combination for both? The only reason I ask this is because I know 1905 is like a semi-semi-key date (if there's such a thing).
I don't know much about gold, but a lot of circulated silver coins that would have sold for over melt at $10-15/oz. are now selling at melt, because of the higher prices.
Depends entirely on condition. It looks like 1905 isn't enough of a "semi-semi-key" to carry any premium in lower grades, but as you ascend the MS scale, it does go up faster than neighboring dates.
According to Numismedia, 1905 $20 in MS-60 lists for $2190. The other dates values start at $2000 and then go up from there so I would say that indicates that some collectors are willing to pay a slight premium for 1905.