Not many D's built, 36 in all I believe. The E model was the earliest version to see combat, with the 54th FS up in the Aleutians. depending on who you believe, some E models may have made it to North Africa, but I don't know that it has ever been proven.
The F was really the first combat 38 with the ability to carry long range drop tanks etc. The E's operated in the Aleutians were upgraded to something similar to this standard
Dan/Slack