Hi Fletch,
Are you putting together an originale GTA?
If so, that's great! And it must be the only one in Indonesia, I would think. I visited Jakarta several years ago and had a grand time!
For the best information about restoring a GTA using the correct rivets, you should contact one of the owners of an original GTA. There are at least two folks here who should have that answer. They are Italcarguy and Borrani.
Here are links to help you contact them:
Italcarguy (aka Anthony Rimicci)
http://www.alfabb.com/bb/forums/send...ailmember&u=35
Borrani (aka Steve Schaeffer [sp?])
http://www.alfabb.com/bb/forums/send...ilmember&u=521
Good luck! Please post some photos!