Hudskit,
The XC-35 was the pressurized, turbosupercharged, "Electra". The fuselage was not an Electra fusuelage, but was rounded. The wings and epinage were the same as the Electra. This one-off aircraft is now at the National Air and Space Museum and will be restored and displayed. Lockheed started the production numbers of the model 10 at 1001 and ended them at 1145. AEs Electra was number 1055. The XC-35 had its unique production number because it was a one-off experimental aircraft built for the USAAC (no.3501). The USAAC received the Collier Trophy for its experimental work with the XC-35.
The rest of the Model 10s that were military are as follows (taken from Lockheed production records and U.S Government records);
XR-20-1(no.1052) was built for the Navy.
XR30-1 was built for the Coast Gaurd (no.1053)
Y1C-36 - 3 of these model 10s were built for the USAAC (no.s 1071, 1073, and 1074)
C-36A (UC-36-LO) 15 commercial model 10s were "impressed" into military service (drafted!) during WWII and surviving aircraft were returned to civilian service.
C-36B (UC-36B LO) 5 model 10Es were also "impressed" into military service during WWII
C-36C and (UC-36C-LO) 7 model Bs were impressed into service
Y1C-37 (C-37 and UC-37-LO) was ordered by the War Department but instead of going to the AAC it went to the National Gaurd Bureau to serve as a transport for its chief.
Would the XC-35 have helped AE IF her flight was a spy mission? It would have been an advantage to fly at higher altitudes in order to conserve fuel, as well as take advantage of tail winds, but the photographic equipment at the time would have been nearly useless at high altitude. Plus the sky in the South Pacific are almost always cloudy. It would be pure chance to get a clear sky upon arrival over the Japaneese mandated islands the Navy was interested in. The Navy had intelegence that the Japaneese were fortifying (military fortifications) their mandated islands, in violation of the Treaty entered into at the end of WWI. Again the XC-35, the one and only one XC-35, is at the NASM and no connection to AE has ever been made.