I don't have easy access to previous builds, they are backed up on cd. I would have to unzip each dated archive to determine the build number. I'm not even sure if I have any v1.3. That's quite old.
I did a google search for FlashFXP v1.3 and v1.4 and came up with the following:
v1.3
http://www.fileplanet.com/files/60000/61184.shtml
v1.4
http://fpweb1.fileplanet.com/files/60000/69549.shtml