No I haven't because mIRC is meant for chatting, not file sharing, in fact there is this sticky about that.

Further, if the person offering the files doesn't have extensions on them, I'd be very wary about getting them.

The only valid use of a filename without an extension, that I can think of, is that it's not actually a file, but rather a directory or sub-directory name. Usually these do not have extensions, and is, generally speaking, a method of determining the difference between a filename and a directory name.