I am familiar with IDF and IDF XE series of carbs. Never heard of an IDE XE...
The differences between the IDF and IDF XE (for extreme) aren't all that great. The XE has some extra sealed bearings, longer jet holders, thicker diaphragms, and heavier springs. It is my understanding that they are essentially an IDF with these areas "beefed up" for the dune buggies. The difference in float level is to aid in fuel delivery when subjected to the extreme "conditions" created in the dunes (jumping, wheelies, rough terrain, etc...)
When I first saw the XE carb they were ONLY factory made by the Italian factory, thus if your carbs were stamped "Made in XXXX" and the "XXX" was anything but Italy, you could rule out it being an XE. (but that doesn't confirm it is an XE either). Now, you can buy an "XE" kit to convert your own IDFs, so it is anyone's guess. Might be best to check with your builder or engine builder and ask them.
As far as float level goes, I've set XE carbs to the same specs as normal IDFs and never had an issue.