Just changing the availability date for something doesn't make it appear.
For example, the default torpedo load-out is scripted by boat type and year in [SUBMARINE_AMMO
#]:
boat type in /data/Cfg/Basic.cfg
This example is for a type VIIB in 1939:
[SUBMARINE_AMMO2]; VIIB
Type=1
Version=0
ForeTubes=4
AftTubes=1
ForeResIntern=4
ForeResExtern=1
ForeResExtra=2
AftResIntern=1
AftResExtern=1
ShellSlots=10
NbYears=7
Renown=3
SNK_MASK=NSS_Uboattype7_SNK_mask
Year0=1939
ForeTube00=0 ;T1
ForeTube01=0
ForeTube02=0
ForeTube03=0
ForeResIntern00=0
ForeResIntern01=0
ForeResIntern02=0
ForeResIntern03=0
ForeResExtern00=0
ForeResExtra00=0
ForeResExtra01=0
AftTubes00=0
AftResIntern00=0
AftResExtern00=0
Z01_00=3 ; VIIB/1
M01_00=1
A01_00=8
SuperCharger_00=1260; GWX V2.1: was -1, so this boat now has GW turbos by default
Snorkel_00=-1
Batteries_00=1265
AftBatteries_00=1265
Hydrophone_00=1270
Sonar_00=-1
Radar_00=-1
RadarWarningReceiver_00=-1
Decoy_Launcher_00=-1
SonarCoatings_00=-1
RadarCoatings_00=-1
Renown0=2500
You would have to change the appropriate numbers in the
red script
However, I don't know the correct codes to be used. Someone else here may know - probably one of the GWX modders.