Is there any way to install the side inserts on the 69 fenders with out takeing the fenders off?

The way to go would be to use clear silicone. I tried emblem adhesive once and it worked BUT if it runs down your paint it can remove the paint. Silicone caulk is much easier to work with. You can use some duct tape to hold in place will the silicone sets.

I thought there was a long topic about the adverse afect of using silicone in regard to future paint jobs? I have used contact cement on cars, boats and anything else I want stuck together, a small bottle is about a $1.50 I don't know if you can remove it after applied it's great stuff. Pete

Pukey is a good way to go, but it doesn't have to be clear, and you don't need huge globs. If you nail it down, you might have a problem

I happened to have blue silicone when I did mine. Just a couple of dabs in the center will work fine. I used a couple of peices of 2-sided tape to hold them place. Almost 20 years later, it was holding strong--slid a thin strip of metal underneath the emblem, and used a sawing motion go remove them.

"Pukey"??

Double sided tape! My friend did that...works well...