Yes they use 747-300 on routes to Hong Kong. and 90% of theri routes.
they also have 767 which they use primarily to Nagoya.
they do offer 747 Cargo but I am not sure it it it belong to JAL or their own color.
JA 8189 (-300) and JA 8154 (-200) are in JAA colors. But occassionally 747-200s and -300s in JAL colors will also operate JAA routes and vice versa. All freighters are in JAL colors only even though they operate JAA flights often.