(Liam Neeson Voice): I don't know where you found this. I don't know how this is possible. I don't know if this is a trick. I can tell you I never encountered something like this. But what I do have are a very particular set of skills; skills I have acquired over very long hours. Skills that only I possess. If you tell me the how this is possible, that'll be the end of it. I will not look for this treasure, I will not pursue the answer if it is fake or not. But if you don't respond to me, I will look for you, I will find you and I will grief you."
A Silk Touch book is best served with Shears, considering how rare they are compared with enchanting. Shears don't break when they shear glass or glowstone, and so serves well as an "editor tool" (a stone or iron tool used for fixing mistakes in building)
I feel a tad sceptical about this...
You have 3 mods downloaded. Are you sure the mods didn't affect the desert temple loot? Find some other desert temples and see if they all have silk touch enchanted books in.
I dont even know if there is a mod that does that? plus i dont know if i have the world anymore . The mods i have are just some basic ones like rei's minimap optifine and Peacful hunger. Thats it.