Hello Pamela, welcome to the forum. I hope we can help you in your quest.
 
A quick search of NARA`s AAD enlistment records brings up 4 Joseph Boatwrights, here is the only one listed being from Georgia:
 
Field Title Value Meaning 
ARMY SERIAL NUMBER  34575413
NAME BOATWRIGHT#JOSEPH
RESIDENCE: STATE 43  GEORGIA  
RESIDENCE: COUNTY 313  WHITFIELD  
PLACE OF ENLISTMENT 4344  FT MCPHERSON ATLANTA GEORGIA  
DATE OF ENLISTMENT DAY 28
DATE OF ENLISTMENT MONTH 11
DATE OF ENLISTMENT YEAR 42
GRADE: ALPHA DESIGNATION PVT#  Private  
GRADE: CODE 8  Private  
BRANCH: ALPHA DESIGNATION BI#  Branch Immaterial - Warrant Officers, USA  
TERM OF ENLISTMENT 5  Enlistment for the duration of the War or other emergency, plus six months, subject to the discretion of the President or otherwise according to law  
LONGEVITY ###  ###  
SOURCE OF ARMY PERSONNEL 0  Civil Life  
NATIVITY 43  GEORGIA  
YEAR OF BIRTH 08
RACE AND CITIZENSHIP 1  White, citizen  
EDUCATION 0  Grammar school  
CIVILIAN OCCUPATION 525  Carpenters  
MARITAL STATUS 2  Married  
COMPONENT OF THE ARMY 7  Selectees (Enlisted Men)  
CARD NUMBER #  #  
BOX NUMBER 0820  0820  
FILM REEL NUMBER 3.242  3.242  
 
If this is your granddad, the next thing you can do is request his military service record from the National Archives in St Louis.
How to Request Military Service Records 
 
There is also much info on locating information & "How TO" in the RESEARCH section of the forum.
 
 
I found an Operation`s Report for the 99th Inf Div for Dec 1944, it has many mentions of the 324th Engineers whereabouts & attachments during Dec.
 
Extract of 99th Infantry Division G-3 Report of Operations.1 to 31 December 1944