Gun Girls who are obtainable in the Pre-release event via Scouting:
FAMAS F1
Skorpion vz.61
SIG SG552
FN P90
Mossberg Maverick 88
HK PSG-1
McMillan Tac-50
FN Browning M1910
FN Minimi
T91 Assault Rifle
Walther MPL
Franchi SPAS-12
Mauser K98k
Gepard GM6 Lynx
Tokarev TT-33
Stoner 63
Mystery Handgun
Guide for the Event by /u/Catbrain External Link to Guide on Reddit