Where are the new dampers to be found/purchased?
There are many online, just search for parts and they will appear.
I use procaliber.com , in WA, I figure closer so faster delivery.
There is bikebandit.com too that comes to mind.
I forget where right now, but the silicon dampeners, a little stronger and last longer. Mine where made by a member locally, who's passed now.
Just get the one piece solid rubber/metal ones for the IS model, not the 2 piece for the others. Basically all GL1500 are the same (for the dampeners), except the early GW ones (6 spoke, instead of the 5 spoke ones).
You might want to add your location to your profile. Might also be told of something local to you.
I personally get the US online price, then go to my Honda dealer in Can. and try to get a price I'm happy with. This way I try to help out the brick-&-mortar business.
And Welcome to the Forum.