I used McMaster-Carr P/N 91020A210 (mcmaster com). They look like the originals when installed. Just push them in with your finger or thumb. They come in packs of 100 for about $15.00. Only nine are needed to replace all of them, and these can be reused if you don't mangle or lose them getting them in and out. You have to squeeze the two parts together with the holes lined up before you push the rivet head in.
Dave
87 GN, purchased new Nov'86, stolen and recovered September '98. Almost back together now.