I found UI sound files in some kind of 2012 beta client (where only 16 weapons existed). Some of them contains fictional weapons names like it was in previous versions of CS (Most of them were re-used).
Here the list of names that refers in files and some of my thoughts for what weapon they are:
Five-SeveN - Five-SeveN, Five-SeveN USG.
АК-47 - AK-47, CV-47.
AWP - AWP, Magnum Sniper Rifle.
AUG - Bullpup.
FAMAS - Clarion.
Glock 18 - Cobra 18 (?), Glock.
G3SG/1 - D3/AU-1.
Desert Eagle - Deagle.
Dual Berretas - Dual Berretas.
P90 - ES C90.
P250 - Exiter 250 (?).
Galil - Galil ACE 22, IDF Sentinel 22.
Negev - IDF Firestorm (?).
MP7 - KM Sub 7.
UMP-45 - KM UMP45.
SG553 - Krieg 556,SIG 556.
Nova - Leone Eclipse (?).
XM1014 - Leone YG1265.
M4A1 - M4A1
SCAR-17 - MK 17, Mark 17,Scarab Carabine 17.
SCAR-20 - MK 20, Mark 20, Scarab DMR-20.
PP-Bizon - Medved-19.
P2000 - P2000.
? - Rapier USG
MAG-7 - Riot-7.
Sawed-Off - Sawed-Off Shotgun.
Steyr ? - Schmidt Enforcer, Steyr Guardian.
SSG08 - SSG 8.
? - Stryker.
Zeus x27 - Zeus, Taser.
Since I'm not sure I'm right in my thoughts, I post it here. Maybe you find it interesting.