Yes, your G.P. Phillips and J.W. Phillips was in McCord's Regiment.
Do you have a link that this information is posted?
Go to the following webpage and type in only "Texas," "Confederate," and every spelling of "Phillips". ..You may want to pare it down with only the first letter of each name of soldier, e.g., for Thomas Louis Phillips, a "T" will bring up all of the names that begin with a "T" then type in an "L" in case he used his middle name. ..There are 1258 men in McCord's Regiment so you'll have to click through the alphabetical listing until you get to "Phillips".
In my 1,022-page book, I only have the McCord's officers listed, but I do own a listing of the whole regiment but cannot lay my hands on it -- recently moved. ..I apologize.