I'm pretty sure that, after all the ribald criticsm of the "green turn signals" at the 67 show, they disappeared very quickly. I left N-V the following June and had spent the last 4 months or so working on the Stormer program, so I didn't keep close tabs on the Commando.
My recollection is that the 3-dimensional plexiglass green domes were dropped very quickly and may not have appeared on the street. The "sphere" concept, for which N-V had paid a PR outfit a lot of money, may have survived in a decal (transfer) one-dimensional form for a short while, before the "Norton Villiers Norton" badge appeared.
I'd emigrated to the US before that happened (left the UK in early July 1968) and was out of touch with the details.