I found a nice pair of four-bulb lamps the other day with an oil-rubbed
bronze finish which would look great in our kitchen. However one of the
units has obviously taken a knock at some point in its life and one of the
stems holding one of the bulbs is (very) slightly out of line.

Am I right in thinking that such finishes are actually a chemical
alteration of the metal's surface, rather than something that's been
'painted on' over the top of the underlying metal?

I think I can straighten things out easily enough just with a small clamp
- but am worried about the surface flaking in the process if the finish is
more of a painted top-coat. The alignment's minor enough that I can live
with it as-is if I have to (and I bet nobody other than me would even
notice!) but the perfectionist in me still wants to put it right if I
can :-)

cheers

Jules