So then wing-mounted engines would not be angled because there's no fuselage and associated air stream to deal with(?).
The airflow ahead of the wing is an
upwash, whereas the flow behind the wing is a
downwash. If the engines on the wing are angled at all, they should be pointed slightly down. I haven't noticed if this is true or not. Too much of an angle would cause the jet exhaust to impinge the underside of the wing.