Do you eat three week old hamburger?
I failed to find the part of the question where the poster wanted to eat it..
..and I would bet that most folks do. Do they put a slaughter date on meat packaged for resale?
Most meat is aged before being put out for sale.
My venison sits in the fridge for 1 to 2 weeks before being processed and frozen. If indeed, the cape and head were held at "just above freezing" for that amount of time it could still be good.. about the same as the chance of it tanning up poorly. So your odds are solid at 50/50..
This would be a good one for tanning in house..