According to the Joe Baugher blog site,:
"In its initial form, the P-47D differed very little from the P-47C-5-RE which preceded it on the Farmingdale production lines. The P-47D had some changes in the turbosupercharger exhaust system which incorporated an adjustable duct and redesigned vents for the engine accessory section. Additional cowl flaps were fitted to prove engine cooling airflow. More extensive armor protection was provided for the pilot. Generally, however, early P-47Ds can be distinguished from Cs only by their serial numbers."
D models started coming off the line in February 43
Also:
"Demand for the Thunderbolt was so great that Republic built a new factory at Evansville, Indiana to augment production of the P-47D. 1050 P-47Ds were ordered from Evansville on January 31, 1942, and the first Evansville-built P-47D (serial number 42-22250) rolled off the assembly line in September of 1942. Evansville-built P-47Ds were distinguished from Farmingdale-built P-47Ds by the use of the RA manufacturer letter code rather than RE. They could be distinguished from Farmingdale-built P-47Ds only by their serial numbers."
Guess there is the possibility of mixed models on the late 1943 raids