Auguries have the guys inside, so reverse! (5)
I believe the answer is:
omens
'auguries' is the definition.
(omen is a kind of augury)
'the guys inside so reverse' is the wordplay.
'the guys' becomes 'men' (guy can mean a man).
'inside' indicates putting letters inside.
'reverse' says the letters should be written backwards.
'so' backwards is 'os'.
'men' inserted into 'os' is 'OMENS'.
'have' is the link.
(Other definitions for omens that I've seen before include "Harbingers, portents" , "Signs of things to come" , "Augurs" , "Portents, prophetic signs" , "Auguries" .)