This listing featuring both the 1915 Dennison Bogie Book itself plus the exceedingly rare 1915 enclosure is the third time this has surfaced within about seven months. Guide value for the duo is $775. The duo listed in July 2016 fetched ~$838. The duo listed in August 2016 fetched ~$810. Comparing condition of the two from last year to this one, this is in third place, the least best. Both the envelope and the Bogie Book have much more wear showing. SGV is $775, but the condition here may work against this listing from achieving that sustainable level. It'll be fun to see where this ends.
03/14 Update: As I suspected, this set in fair condition ended well below SGV - at $556.99. Condition is so important that there was almost a 33% decline in the money this brought compared to the only previous two examples sold on eBay.