While some minor details are off (the GUI -> Xemacs thing was probably more accurate several years ago), you're basically right. Emacs Lisp is kind of a crappy Lisp dialect, but it's a very accessible way to learn the basics, and if you use Emacs, quite immediately useful.
I wish I had a better suggestion for learning elisp, but I mostly picked it up from the Emacs Lisp info file included with Emacs (http://www.gnu.org/software/emacs/manual/html_mono/elisp.htm...). I'd been reading SICP already though, so I already understood the fundamentals of the Lisp family. The best intro I've seen to Lisp is _The Little Schemer_, but keep in mind that Scheme is the "clean and minimalistic" dialect (for better and worse).
I wish I had a better suggestion for learning elisp, but I mostly picked it up from the Emacs Lisp info file included with Emacs (http://www.gnu.org/software/emacs/manual/html_mono/elisp.htm...). I'd been reading SICP already though, so I already understood the fundamentals of the Lisp family. The best intro I've seen to Lisp is _The Little Schemer_, but keep in mind that Scheme is the "clean and minimalistic" dialect (for better and worse).