Slightly. The JPN Rev 1.1 ISO is approximately 1.2GB versus the USA version’s 1.4GB, due to removing redundant English text localization files.
Stay tactical. - The Retro Tactics Team
The Japanese version (subtitled Souen no Kiseki ) was released first. It contained several bugs and balance issues that were later fixed. The "UPD" (Updated) designation typically refers to the dump. Here is what changed: Fire Emblem Path Of Radiance Japanese Rom UPD