The Enterprise Edition also bases its work on the the Base Community theme but expands the base templates with the enterprise default theme.
So yes, the "basic" base theme is the same.
But: because of the expanded functionality of the Enterprise Edition there may be some changes you have to make. Especially if you base your theme on the default enterprise theme which may be the case.
While the community default/default theme is very lean (only one widget XML file, one line of translation) and therefore you base is very much the base/default theme, the enterprise enterprise/default theme has quite some changes.
In EE 184.108.40.206, it consists of:
- 1 widget XML file
- 29 layout XML files
- 1 translation file (the same "important" one as in CE default/default)
- 246 phtml files (because the enterprise default theme just looks different from the community default theme and because of extended functionality)
Of course numbers don't tell everything but you do see there is some work to do.