Restoring this fantastic lamp  

Paulanna is right
That is some very accurate advice on metal stretching. I have tap-tapped on car fenders before, and its really easy to make a bigger mess.
When you find a metal shaper that is so good, they can chrome their work, then you have someone qualified.

I'll be very careful...
I'll be very careful whatever I decide to do with this lamp. I would hate to see that I made it worse instead of improving it...
Paulanna, do you know if there is any way to professionally restore a dent without damaging the paint as well? I'm not interested in filling the dents and paint them over. Then I think I'd prefer to leave the lamp as it is. But if there was an option to leave it to someone to do the job right, I might consider it.
Btw, on what do you base your opinion about the pictured lamp? I couldn't tell it has been restored. The paint finish looks very much like the one I have, but of course I also wondered how a 50 year old lamp could be in such perfect condition.
His lamp is for sale at 1900 USD and I found mine for 200 USD, so either way I felt I got a good deal.

$200!! - Ok I'll give you...
$200!! - Ok I'll give you $400. Don't say I'm not a generous man.
Seriously there are guys out there who can do magic with dents and twisted metal but they're a dying breed....all I can say is that if you know anybody who runs a classic car see if they can get a first hand reccomendation for a good old fashioned tinbasher who'll know exactly what can and can't be done.

It's a beautiful lamp
At a great price!
leave it alone !!!
please