The stakes were once tall enough to melt down over the lens. If a original lens wasn't properly removed you may not have enough stake left. Donor abs plastic is what I use. Epoxy would work.
Yeah that was and still is the common practice. Of course on assembly lines they melt the stakes in a machine. Adhesives in machines gets very messy. Chemicals that would molecularly bond the plastic also being messy can ruin a clear lens so they don't use those.
Anyway... I just use a soldering pen and donor material where needed to recreate what the factory did.
The lenses are most likely acrylic and the bezels are ABS. Melt temperatures are nearly the same on the two materials so they will blend together with a soldering pen. Just saying!