Sadly it isn't. RPG Maker VX gets extremely buggy if you try to transfer the Save Data over to a previous version. Not only that, but Patch 1.3. has a LOT of changes to the base game, so it'll be better just to restart on the new patch.
Recent community posts
BLANK: Patch 1.3 is released! comments · Replied to cyanprime in BLANK: Patch 1.3 is released! comments