Earliest P-38 orders according to the USAAF list of contracts,
Contract AC-9974 dated 23-Jun-37 for 1 XP-38
Contract AC-12523 dated 27-Apr-39 for 13 YP-38
Contract AC-13205 dated 16-Sep-39 for 66 aircraft, built as 29 P-38, 1 XP-38A and 36 P-38D
Contract AC-15646 dated 30-Aug-40 for 410 aircraft, built as 210 P-38E, 75 P-38F, 5 P-38F-1, 99 F-4, 20 F-4A, 1 F-5A