I have always riveted them also.
Do not use a countersunk head rivet, it can spilt the plastic as it tightens. You may have to grind a little if the excess off the back side for clearance depending on the application. Grind just the excess bulged out body of the rivet, not the shank. I did a 69 Camaro a month ago and had to grind a little off with the belt tool after installation.
I will be doing my 89 this weekend so I can't say yet if grinding is needed.
Good stuff! Door panels can sure throw some unexpected curves every now & then. Some are surprised when I tell them that I will probably spend more time on their door panels than their seats. Doing things that they'll never see, but if I didn't, they sure would.
I was just starting my first coffee about the time I posted. Didn't even occur that I should offer some info. Duuuh.
When riveting, get the seal taped into place & mark the center hole & the spots at the ends to be drilled. The end ones about a 1/2" back from the end of the seal.
Evenly divide the spaces in between with marks. Depending on those 1/2 distances, you may end up doing 2 or three for a total of either 7 or 9 rivets. Maybe 11.
It's not how many you use. It's about the spacing. Too far apart & the seals could start to warp into wierd shapes after a bit of use. Same with the even spacing. Randomly installed rivets can create probs, too.
I've heard some guys say to start from one end & work to the other.
If that's what they find works for them.
I prefer to start from the center & work out, alternating from one side to the other, drilling each hole as I go. Don't pre-drill them all at once.