Are you saying you are using 14, and have some styles from 13 you want to use? Or are you saying you're in 14, have a DB built in 13, and want to use some of the styles from 14 on the older DB.
I think you start by saving it as a custom style, which you can paste to the objects.
I am working in FM14. The layouts are based on a Theme created in 13.
None of the new style attributes are even available in the Inspector.
I haven't upgraded yet, so I cant say for sure, but if you go to a 14 based layout (new or from a starter solutions, with an object, or create an object with the attributes you like, copy that new style and paste it onto an older object, it wont work?