Here's the latest from the CMPicon forum, ask Orest:

Orest, How are the Criterion Kragicon barrels configured? Is there a front sight base installed, pretty much is my biggest question, or are they 'slick', and need to have one installed? Thanks.....

To which Orest replied:
you have to remove the sight from the take-off barrel. they are 'slick'.

I'm going to interprete that as "without rear sight holes too" but that's ok, saves some indexing headaches. For those of you who get one, remember, they're M4x1mm, and you're not going to find a tap that size. M4x.7mm will be as close as you're going to get I believe. What does that do to "as issued"? I'd think little, it certainly wouldn't give anyone any sort of advantage. But what about 1901 windage pivot screws? And what if I decided to use socket head cap screws instead of slotted?