Dating A Case Of OLD Glenlivet, Drinkable? Collectable?

[spectrrr]

Hopefully someone can recognize the era these bottles were produced in? It seems that it was before Glenlivet started marking the age, and it came in a wooden crate with a series 112 tax stamp.

photos posted below, click any one for a higher res photo. External gallery here: http://imgur.com/a/GHSij#Gp9Hy

I found this case while cleaning out the storage room in my mother's house. She has no idea of its history and surmises it belonged to my late father. Looks like at some point in its history there was some water exposure at about the mid level point in the case, but it must have happened a long time ago because her storage room is/was/always has been quite dry. Unfortunately it's also not very insulated, so my guess is they have been exposed to higher temps than is commonly considered healthy for long term storage.

I want to figure out two things. How drinkable it is likely to be, and how collectible it is. If it's not collectible, I'll simply open and enjoy it for what it is. However if it has more value as a collectible than in drinking, I would gladly sell it and use the money to obtain something more special in the drinkable category. (a few good bottles of 20+ year? yes please!) I am absolutely a scotch drinker, but not a collector.

Thanks in advance for your help!!