Hmmmm.....let's see.
An overhaul, is the same as a check up, is the same as an adjustment, is the same as a re-pad, is the same as a full restoration.
I'm pretty annoyed at the moment because my main Alto went in for a leak check. My tech strips the whole thing down, tells me it's the best "Crat" alto he's seen as far as all the mechanichals etc, but that it needs a full repad. Then you get a "vaguely, possibly, maybe, depends upon," quote. A week later,a call on the phone tells you that your horn is ready and the bill comes to AUD$ 1000 +.
My tech is perhaps the best in the business, but the prices have gone steadily skyward. I always budget $400 at least above his first quote.
To answer your question, from a players point of view, an overhaul means a full restoration on the mechanical side of things at least. You might tell your tech not to worry about cosmetic stuff, but all pads, tone holes, springs, rods, posts and pivots etc, should be made true.
It's gonna be damned expensive and is really only worth the cost if you're a serious player. As much as I whinge about the cost of a good tech, it's impossible to guess a quote until they've stripped the horn down I suppose. I'll feel better when I get the horn back and play it.