It is possible to restore anodized aluminum trim pieces and yes it can be expensive.
The current anodizing has to be stripped.
The part is then repaired and polished.
And last it has to be re anodized.
I think on many parts the cost is worth having an original part that fits well rather than a "corvex" piece that usually does not fit very well and has to be bent and tweaked into place.
On a mustang the cost of an NOS part may be less, I can't say for a galaxie.
I have had King Of Trim (
www.kingoftrim.com/home) in California do some pieces for me and they turned out really nice.
I have also had Dave Kosmann (
www.1960impala.com) in Caldwell Idaho do a few pieces and they also turned out very nice.
My dad and I are restoring a 1959 impala and those cars have a BOATLOAD of stainless and anodized aluminum parts, lucky mustangs have relatively limited trim.
The anodizing on aluminum can be tricky and if the person does not do it just right it comes out hazy.