Looking through this report (which is for 4 February):
http://www.351st.org/351stMissions/M...Mission77.html
It appears that GH-577 was the Alfred Teves Main Works: Aircraft Parts Plant - Frankfurt-am-Main, Germany
However, there are other reports:
Here for a mission on 5 November 1944 where the target is the Frankfurt Marshalling Yard where they seem to also give the target as GH-577.
http://351st.org/351stMissions/Missi...ission228.html
and here again for a 11 December 1944 Mission where again GH-577 is the Marshalling Yard:
http://351st.org/351stMissions/Missi...ission241.html
Or this one where target GH-577 seems to be the Aero-Engine Parts Factory, Frankfurt, Germany.
http://www.351st.org/351stMissions/M...Mission86.html
I believe the target codes were the same ones used by the RAF.