* for the Widow, you could use the Zersium rifle (w_brifle_30) stats adding something like Extra Range Damage Type-piercing or a Bonus Feat like Improved Sniper Shot. If you add the Master Sniper Shot instead of Improved, I'd reduce the Damage Bonus Energy-Damage 1d12 to 1d8 or so otherwise it will be a little overpowered.
* placement: I know it sounds odd but if you want full compatibility you can just add the new rifle to merchants like Dahnis at Nar Shaddaa (kexsstore003.utm) or Akkere at Dantooine (store_adum001.utm). They don't sell weapons exactly that's why no one modifies that ... also human Geg at Onderon (store_geg.utm) although this one is more likely to have been edited. And I'd set a price from 500 to 1100 to the rifle otherwise it will be hard to get the credits ah?
* for the Widow, you could use the Sith Sniper rifle (g_w_blstrrfl002.uti) stats adding an attack bonus 1 and Damage Bonus-Piercing 1 OR Keen in this last case, or it will be overpowered probably.
* at Kashyyyk m22a rim (the level where you arrive) there are few containers and crates that don't repeat in game, you might use them if you don't want to have rifles all over the game ... this ones for example: kas22aa_cont_04.utp or kas22aa_cont_06.utp. Free widows deliver in this case? ... otherwise, you have Junix Nard selling stuff (kas_junixstore.utm) in Tatooine's cantina, other unique utm too, and not much used IMO.
same places-merchs could be used for the pistols, right?
still have to see about pistols stats ... oh almost forgot, considering there's already a Sith Sniper rifle in KotOR, while not name the Widow Republic "Widow" Sniper Rifle or the like? Darth Payne will be glad with that if I recall ...
That's fine to me, and if any one want to change the weapon's stats theirselves it's not so hard ^^