As bullion / possible collector item ! What happens if Gold goes to 30k/ oz ? I don't know, but when I sell junk silver as WL halves, might as well be 1964 JFK's. I think the collector value of a SG20 gets lost in a time of high metal values. Barber and seated coins melted in 1980, and BU bags of dollars, etc.
If spreads are tight (as they are now), I think it's a good time to buy old US gold near melt. However, I doubt you'll ever see that much of a premium (unless you find a deal on a really high grade coin sold raw -- but be careful (watch for improperly clean coins and counterfeits!!). In any case, I think old US gold coins are a lot more fun and interesting to show people. I bought this for a hair over $1600 back in April. It contains 0.967 ounces of gold so melt at current gold prices is around $1541. So for a few bucks, you get a coin over 113 years old oozing character and history -- and as gold rises, this will rise right along with it, just like the dime a dozen bullion gold coins.