Sorry to be so late with the book info...Got tied up with the neighbors and the VP Debate...
The book is titled "The AR-15 Complete Owner's Guide" by Walt Kuleck, with Scott Duff...Vol I, Second Edition...
Chapter Seven deals with assembling your own upper and has some insights that the author observed while building his, in conjunction with the Army and Marine Technical manuals.. (If you really get into the AR platform, they are also worth reading)
The book covers almost every aspect of the AR-15, as well as history and variants...