INF files say:
%VENDORMDM% = Modem2, USB\VID_201E&PID_10F8&MI_03 %VENDORDIAG% = QportInstall00, USB\VID_201E&PID_10F8&MI_00 %VENDORAT% = QportInstall00, USB\VID_201E&PID_10F8&MI_02 %VENDORNMEA% = QportInstall00, USB\VID_201E&PID_10F8&MI_01
so yeah #3 should be primary + data like you say.
INF files say:
%VENDORMDM% = Modem2, USB\VID_ 201E&PID_ 10F8&MI_ 03 201E&PID_ 10F8&MI_ 00 201E&PID_ 10F8&MI_ 02 201E&PID_ 10F8&MI_ 01
%VENDORDIAG% = QportInstall00, USB\VID_
%VENDORAT% = QportInstall00, USB\VID_
%VENDORNMEA% = QportInstall00, USB\VID_
so yeah #3 should be primary + data like you say.