2-series aluminium bumpers - upside down?

I have a good straight aluminium 2-series front bumper, which I am
considering fitting to my '80 model as the existing one is slightly
damaged at one end.

The problem is that the good bumper has a pair of holes in the top
where someone presumably mounted a pair of extra lights. I don't
want the holes in the top, and am wondering if there is actually a
top and bottom on the aluminium bumpers, or can I flip it up the
other way? It'll be getting painted black before it goes on, so
existing scratches, etc. won't matter...

Obviously, whichever way up I fit it, I'll have to drill the set of
holes for the '80 front spoiler...

 

If you're painting the bumper, why not fill the holes first?

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

By the time I add aluminium MIG or TIG welding cost to the exercise,
plus the extra work of grinding the welds back, I may as well go to
the wreckers and look for another bumper. For the sake of two
small holes, it just doesn't seem worth it.

I have some stainless-covered GM bumper bar bolts, and I'm thinking
that if the bumper won't invert, I can fall back on putting them in,
but I'd rather have a nice clean top surface on the bumper.