1 copy of any promo (and 12 promos max) is only a rule if playing in PFSACG organized play. If playing a home game, you can include as many promos and as many copies of each promo as you wish.
Agreed with the above. I have four or five copies from the subscription and have all of them in my Skull & Shackles box.
I believe you're thinking of the Blessing of Zogmugot as that was the blessing promo for S&S and the one that they provided 5 copies of via subscription.
I remember one of the developers for the game stating that it isn't recommended to use multiple copies of this blessing as it can be rather powerful (can't find the specific post at the moment), though you can do whatever you like in your home game if it's fun for you. However, I believe that this rule makes it so any blessing that shares the god's trait is considered to meet the "matches this card" requirement for recharging. Therefore, if you play a game mixing in either or both of the Goblin decks you will eventually have 2 to 4 more blessings with the Zarongel trait in the mix that can potentially let you recharge the Blessing of Zarongel.
A couple of friends and I are currently gearing up to play a super-goblin, non-organized-play edition of Skull & Shackles using both of the Goblin decks and as many goblin promos as possible (I may or may not break the normal 12-promo limit, but will definitely be using all five of my Blessings of Zogmugot). I'm really looking forward to having Poog, Mogmurch, and Reta sail the Inner Seas, wreaking all kinds of havoc.