okay so idk how this works but i think a new pistol would be a nice touch to the game so i did some search and found the FN57 Laevatein on the wiki which im leaving a link below tho as to the mod couldnt find one so i couldnt tell if i searched nor know where to search beside google
Link to wiki page for gun with pictures and infos:
FN57 Laevatein
For original version, see FN Five-seveN. FN57 Laevatein is a Transcendent grade pistol in Counter-Strike Online. A pistol that uses 50 5.7×28mm explosive…
cso.fandom.com
as to the link a found i basically found its cousin which is quite similar on game banana:
FN57 Ancient Bringer Mod for Counter-Strike 1.6 | CS1.6 Mods
A Counter-Strike 1.6 (CS1.6) Mod in the Sig P228 category, submitted by Theone1337
gamebanana.com
Hope this would be possible if it does might put some more effort into finding more 
