A couple more DI's.

[Geo3310]

Just found these and would like to get some help in identifying the units. Thank you.

[PATCHRAT]

1st U.S. ARMY OPERATIONAL TEST COMMAND

http://www.tioh.hqda.pentagon.mil/Catalog/Heraldry.aspx?HeraldryId=14774&CategoryId=8834&grp=2&menu=Uniformed%20Services

 

I believe the DI you have is the first version; check this link for the current SSI and DI

 

http://www.tioh.hqda.pentagon.mil/Catalog/HeraldryMulti.aspx?CategoryId=2989&grp=2&menu=Uniformed%20Services

 

 

2nd U.S. ARMY FIELD ARTILLERY CENTER AND SCHOOL

http://www.tioh.hqda.pentagon.mil/Catalog/HeraldryList.aspx?CategoryId=7008&grp=2&menu=Uniformed%20Services

[Geo3310]

Thank you. I'm always impressed by your wealth of knowledge.

[patches]

There's also a way to know time period of DIs, the Arty one in particular, which is the oldest authorized DI of the two, and that is seeing what hallmarks are on the back, so what does your Arty DI have on the back?