Ok after reading it again they where fully converted to P-51B/C's in July of 1944. As far as I can find out they where still flying a mix bag of aircraft of P-51B/C's along with P-51D's up till at least March of 1945. The group mearged to become the 477 composite Group June 8th 1945 and by Febuary of 1946 the group had just a dozen P-47N's.
As far as the D's go the book is limited. Best I can do is give a guess with the info I have. This profile of a P-51 is dated october 1944 but the earliest picture date of a P-51D that I have found info on is noveber of 1944.