I had no luck finding a MACR on fold3. Perhaps others will have better luck.
There is mention of the Gunn loss on page 3 of this newsletter:
http://www.455th.org/Newsletter/PDFs/Spring%202005.pdf
It is not clear that the man making the request ever got a reply (at least not in subsequent newsletters that I could find). The newsletters were ended in 2016. The mission number of the loss was Mission 171, flown on December 26, 1944. There is a little info on mission 176 on page 132 of this:
http://www.15thaf.org/304th_BW/455th...20Missions.pdf
There is a photo of the Gunn crew on page 6 of this:
http://www.455th.org/Newsletter/PDFs/Spring%202002.pdf
Some of the names are mis-typed , e.g. Dana I Kelleher and Eugene B Scerbo:
http://www.legacy.com/obituaries/ber...y&pid=16831520