I put together several kits, 1 TC Hawken, still hunting with it. 2 of the CVA Kentucky Rifle Kits with the 2 piece stocks.  Second one I still have and hunt with.  I did not use the brass insert to join the stock, I used black cow horn.  You have to look close to tell its 2 piece.  I browned both the CVA kits, easy enough.  Stock was stained with Laurel Mountain Stains, I used a mix of cherry and walnut then finished out with Tru Oil but the next one will be with a mix of Watco Teak oil / Formby's tung oil.  I have used this on several stocks and really like the finish plus its tougher than the Tru Oil (my opinion).  I don't worry about trying to wet the stock and sand out the fine "hairs" that come up, that is taken care of when I wet sand the Teak/Tung oil in using progressively finer wet dry sandpaper.  I have also added 4 inlays, wire brushed the brass and let nature take its course dulling the finish.  So far, this one has taken 5 deer.
As far as iron sights, try Dixie Gun Works, they have anything you might want along with kits.  Good luck and enjoy your kit.