Though the 1867 $20 is available by the hundreds in Mint State, it rarely comes as nice as Akers suggested years ago. He wrote that a number of "choice or gem quality" examples existed, but they simply have not shown up yet -- certainly not at auction or in the population reports at PCGS or NGC. In fact, the best certified examples are a few pieces of MS63 quality. Thus, this date should now be considered under-rated in top condition.
Eric P. Newman Numismatic Education Society - Heritage 11/2014:3377, $258,500
Heritage 6/2014:4917, $28,200
Heritage 4/2006:2163, $28,463 - Heritage 8/2006:5643, $34,500
Stack's/Bowers 4/2016:13229, $13,512.50