Upon restoration I noticed 2 holes (left and right of brass filters) that had some debris in them. Not to sure if these holes must extend all the way into the cock's chamber.

What is their purpose & should they be totally penetrable with a thin wire into a chamber? Mine seem plugged.

Thanks

Those small holes should not penetrate through. They are used during manufacture of the part. The fuel enters through the small pipes with the brass screen (filters).