It took some time for me to figure this out (slaps forehead). I should have been more observant. The initials LB stand for designer Luigi Badia.
I know of two RHM products with his initials on the obverse.
1992 dated Princess Kaiulani 1/10 oz silver
1991 King Kalakaua Akahi Dala 1/oz silver
Here is a plaster model of the obverse die with the LB initials.