Success!
The 14 ribbed gaiters from the G/S or ST models are what I remember from years ago:
o https://www.realoem.com/bmw/enUS/showparts?id=0348-USA-06_1980_2471_BMW_R_80_G_S&diagId=31_0318#31421241666
o 02 Ring 2 31421241669 $6.97
o 03 Rubber boot 2 31421241666 $16.90
o R 65 GS, R 80 G/S, R 80 ST (80-92) R 80 G/S Fork slider
They need the neoprene ring. There's a breather hole in the ring that attaches to a dowel on some bikes, but on the LS the ring sits low because it fouls the instrument bracket, so it doesn't need the dowel to expel air.
Pic shows the 11 ribbed version on left and 14 ribbed version on right.
Thanks all.