It had been sometime since i had watched the first movie,but i had recently won an auction for the first film on Superbit.To my knowledge it is very rare,but i have to tell you the picture and DTS Sound is absolutely amazing if you have a sound system.IMO i think the sound is better than the Blu-Ray version but that’s just me 
but if you ever see them going cheap don’t let them pass as there also a Japanese releases only.I hope to get my hands on GB II Superbit in the future.