Hi Bob,
While I was installing my wiring harness into the convertible I happen to remember this thread.
Attached are pictures of flashers from my 67 04B LOS and 05B NOR, both with rally sport.
I'm not sure if RS has anything to do with which flasher was used.
The LOS flashers were in the car when I bought it in 1980 with about 53000 miles. Even then it sat in a garage for 6 years before being sold to me.
I only put 5000 miles on the car since I've owned it and never had flasher issues. The yellow flasher housing is plastic.
The NOR has what looks like its original fuse panel mounted flasher and it has the 'DOT' stamp. It was there since I bought the car in 1979. That panel still has many color coded original fuses. The under dash flasher is a recent replacement (not pictured).
Mike