Doug's headers with studs?

Probably been asked before but couldn't find any info...

I finally bucked up and ordered Doug's headers to replace my Hooker style..I had a hard time with studs in the end bolt holes for the headers so I used bolts, but I'd like it if water didn't pour out of my heads when I pull them out in the future.

Are you guys with Doug's headers able to run studs in those holes? I can't tell in the picture if they give you studs or not....damn Internet.