Hi all,
This is actually a query concerning most brit bikes made between 1964 and 1973, but I will post it here, since by number most Commando models had the L679 lens.
The rubber gasket carries part no. 54571677. The NOS sample shown features a lip surrounding the lens.
However, all aftermarket rubber gaskets do not have this lip. There is a US company reproducing the rubber gasket and they claim their original (?) sample doesn’t feature a lip.
This kind of gasket appears to seal poorly…