That orange Marshall was most likely not his, that Fender is though and I'm pretty sure it's the same as used on the LAD album which is also used on the new Miami album
I managed to pull some info from JT Longoria (bass + engineer on LAD an Miami) and he said some details about equipment, mics used and the mixing etc.
There's a 2006 Izzy pic from the airport when he was playing with the new GN'R where he signs some guitars, he's wearing a blue jacket on it and behind him is a guitar case and small 15W / 20W amp, probably Marshall. He's said in 2001 that whenever he travels he takes with him a hollowbody guitar and that amp, it's great in hotels he said and he can make outline's for songs that way.
Anyways, for Izzy equipment in GN'R and solo go here
http://www.chopaway.com/equipment.htm or here
http://www.chopaway.com/pun/viewtopic.php?id=11