Originally posted by Apo!!o:

This is my first help for you regarding the gold bars, when I didn't made a misstake it was not explained in the good and big easter egg discussion. If someone knows more details, please leave a comment. I will update this post.
Collect all 6 gold bars and go to the crafting table in the church. This will craft a weapon: PPSH in my case. Maybe its everytime the same. Will not take it, cause my weapons are too god. But this for a first step.