Perhaps...
Reflection might be preferable, particularly where code has been obfuscated - perhaps in a commercial product. This is how both Java and .Net prefer to discover information about libraries during design and at run time.
However, as Simon points out, this method depends on all libraries being present. There could be other issues, for example where hidden methods exist, and could be important to the model.
Disassembly might overcome the above limitations, but has additional costs, in both time and complexity. I'm guessing, but there could also be 'clutter' if there were a lot of internal plumbing in the libraries.
Sparx has provided us with two approaches. Most of the time, if you've got the entire library set available, these will produce the same results - try importing the entire .Net or Java library set both ways and compare.
So, try the default that EA offers. If you don't get the result you want, use the other setting.
[Sparxians: hopefully I'm not too far off. Please correct me if I've misstated your case.]
HTH, David