Thought you might want to check this out, please copy and paste link into your web browser some interesting reading. Here is link below. Also it looks like your looking for GO#76 dated 22 Sept of 1944 I've seen several sites refer to GO#76 not #77.
Hope this helps.
Dear Mr. Ebbeson,
Thank you for posting your request on History Hub!
We searched the “War Department and Defense Department Publications and Issuances, ca. 1941-1970” in the Records of the Adjutant General's Office, 1905-1981 (Record Group 407) and located War Department General Order #76, dated September 22, 1944. Section I indicates the name change of the hospital. For access to and/or copies of these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
We hope this information is helpful. Best of luck with your research.