USAF Strata Blue Paint Code
PPG paint code for Strata Blue is 17634. Gillespie Coatings paint code for Strata Blue is 25045.
Rapco in Bowie, TX carries 25045 USAF Strata Blue. General Jim's in Clare, MI carries it also.
The yellow for door markings, etc. should be Insignia Yellow, but you can use Testors 1214 Gloss Yellow.
From an old military manual:
b) Truck, Ambulance, 3/4 Ton, 4x4, M43 (Series).
(1) The word "Ambulance" will be marked in 3 inch high white letters, centered three-quarters of an inch above the windshield.
(2) A 3 inch red cross on a 4 inch square white field will be marked to each side of and in line with the word "Ambulance" above the windshield.
i) Ambulance Color Markings. The following colors will be used for ambulance markings, as applicable:
(1) Gloss red, Color Chip No. 11136, and Gloss white, Color Chip No. 17875 on vehicles painted gloss or semigloss.
Photo credits to their respective contributors- thanks!