IIRC there is a short piece in Regan's Bourbon and other fine American Whiskies that tells the tale of the bottling, also in one of Murray's books. However, I have both the 20yo and the 16yo Gold wax and both clearly state 1974 as the date of distillation, the 20yo even says it was spring of '74. The 16yo says the barrels were brought to KY for final aging and bottling in 1989, so it would seem the 20yo spent 5 years there and the 16yo a yer or less before being put in stainless. Julian has confirmed (somewhere on this board) putting the Hirsch in stainless, as he currently has done with his rye.