U2412M, CCFL or White LED?

All monitors with ol' backlight and standard gamut very close to sRGB or smaller gamut are "CCFL".

All monitors with LED backlight and standard gamut (very close to sRGB) are WLED (white led, its a blue led with phosphors that take blue light and glow in yelow, thast how WLED white is made)

ALL new models with standard gamut monitors or laptops are WLED: Inspiron 13 7000, U2412M, U2414H, P2414H, U2713HM, U2415, U2715... Dell 5k monitor has led backlight and I think that sRGB gamut so this is a WLED too.

A monitor with GB-LED backlight (RG_phosphor family in Xrites names) are widegamut monitor with 99% AdobeRGB coverage and red gamut beyond AdobeRGB. It is made with a blue and a green led and  phosphors that take this light and glow in red. These are monitors for photography like U2413, U2713H, U3014, UP2414Q and UP3212Q

A monitor with RGBLED backlight is a very expensive monitor with a gamut greater tah AdobeRGB. They are not used in new models because they are expensive to manufacture so GB-LED is choosen for new widegamut monitors.

If you could spend a litle of your time reading ArgyllCMS/DispcaGUI documentation I recomend that you USE these programs, not Xrites color munki software. They are free software (code and binaries) and are more porwerful and accurate by far than color munki software or even i1Profiler. No drivers are needed fro i1DisplayPro or Munki Display. Just plug, open DispcalGUI, sleec your spectral correction (WLED, like in Xrite's software) and configure your calibration target.
Lots of threads in this monitors sub-forum regarding U2413/U2713H GPU calibration with DispcalUI are suitable for other monitors, just remember that instead of RG_phosphor spectral correction you should apply WLED correction