I did mine a couple of years ago. It was not very hard at all. The rivets you see in the pictures are actually plastic and you usually get new ones with the new weatherstripping . Everything else is is held on with screws and cement. The hardest part is cleaning all the old stuff off prior to installing the new rubber.
Oops, just noticed you are writing about a C1, mine was a C2 top. The new weatherstip should come with all the correct materials to install it. If you have rivets, they should be able to be drilled out and replaced.