It would seem to me that these questions posed to different people will yield different answers. I will start at the end..... '...(if) the price is right, would it still be worth considering?' Sure, if the price is right. For me, it would have to be a very low price due to the pitting. So low in fact that I wouldn't expect to come to agreement with the seller. But, if one doesn't try to agree, one will never know. The price tag usually lets me know if my offer would be insulting, but I wouldn't walk away before asking if there is any room to negotiate. Honestly, I have little use for a gun that is relatively common and in poor condition.
As for disassembly, that all depends upon the seller. Looking under grips would on the surface seem a simple task, and not too much to ask. Popping off the sideplate could be an entirely different story. If I was the seller, I would not allow a prospective buyer to pop a plate unless there was a compelling reason to do so, and I would likely reserve the right to do it myself. And then you are at the mercy of my mood and availability to spend the time. If the buyer is known to me as very competent with this task I might consider it. It really isn't too hard to evaluate the condition of an action without taking it apart, so I would likely draw the line somewhere well before removing a sideplate.
I would have to evaluate the situation by asking myself why it is that I want it - what purpose will it serve to me, and what is the value of a handgun that serves that purpose?
My EDC is a 649. Been carrying and shooting it for years. Thus far, no pitting, so I'd likely not give a pitted one very much attention.