Most likely. I admittedly don't remember what Julien was like in the Red and the Black (I remember reading and loving that book in high school or junior high - but that was also over forty years ago).
But yes, I think you may have nailed it. I had a writing professor warn me once about writing about myself or inserting myself into fiction - you'll either make yourself too good to be true or incredibly awful.

I think Whedon kind of did that with Xander. And the other writers worked to deconstruct it - which I think Whedon loved. He loved to deconstruct things.