Yup, it is. I remember an opening that I missed by a day from the Maldive Islands back in the late 1970's, they had a 60 mb outlet that was heard around 0000. I heard about it a day later and tried for about 60 nights in a row but it never propagated again.. Fellow BADXer Jerry Berg got a very nice QSL from that.
Speaking of Diego Garcia, they QSLed my reception from September with a full data card and bumper sticker. Address: AFN, Broadcast Center, 23755 Z Street, Building 2730, Riverside, CA 92518, card signed by Tansy Nguyen, ZCC (SW), USN
PDF copy attached.