According to Gamefaqs, the IDs for the JP releases of SoTN are:
Original: SLPM-86023
PlayStation the Best: SLPM-86073
PSOne Books: SLPM-87328
http://www.gamefaqs.com/ps/196885-castl … night/data
In redump releases there are three versions, 1.0, 1.1, and 1.2. These pages imply that 1.2 refers to the Playstation the Best and PSOne books releases:
http://redump.org/disc/4684/
http://forum.redump.org/topic/4927/ps1p … ds-in-dat/
However, I checked the redump IDs:
1.0 - 86023
1.1 - 86023
1.2 - 86023
They're all the same. 1.2 should be different. It should be SLPM-86073 or possibly SLPM-87328.
Why is this significant? The SLPM-86073 release includes bug fixes and a few minor content additions. From a technical standpoint, it is the best PS1 version of the game.