AGM-130A contains an Mk-84 warhead, AGM-130C contains a BLU-109 warhead.
Here is a photo for the AGM-130:
[img]http://www.designation-systems.net/dusrm/agm-130a.jpg[/img]
And another:
[img]http://www.designation-systems.net/dusrm/agm-130a-1.jpg[/img]
As you can see, only the mid-section of the warhead body is visible when it is "embedded" in an
AGM-130, both the nose and the
tail sections are covered by the
AGM-130 assemblies. Because of this reason, I can hardly see any visual differences between the A and the C version. I tried to find a reliable photo source but I failed - reading all the descriptions I came to the conclusion above.