While searching websites for an answer to a question i had as to whether engineer units had thier own portable sawmills or used any locals mills to supply lumber and timbers for bridges or buildings etc. I came across the website for the 9th Infantry Division. Lo & behold on one of their pages are copies of Field manuals including 4 Engineer FMs:
FM 5-5 Engineer Field Manual, Engineer Troops
Dated: October 11, 1943
FM 5-15 Field Manual, Engineer Corps, Field Fortifications
Dated: February 14, 1944
FM 5-20 Field Manual, Camouflage, Basic Principles
Dated: February, 1944
FM 5-20 Field Manual, Engineer Corps, Comuflage of Bivouacs, Posts, etc...
Dated: May, 1944
FM 5-5 gave me the answer, they used both. This FM layouts the types, organization & operations of all the different types of engineer units. It sure is great to have an online reference for all this info!
Home :: 9th Infantry Division, 39th Regiment, Easy Company
The manual page: Lists Infantry & Engineer manuals they have.
FM_5-5_Engineer_Troops_1943.pdf
FM_5-15_Field_Fortifications_1944.pdf
/FM_5-20C_Camouflage_of_Bivouacs,_CPs,_Supply_Points,_and_Med.pdf