I have owned an upper mast segment painted with white colour. It has been just only white paint on the aluminium for to have a better styling. The paint has not any influence to the behaviour of the spar. All I remember: It must have been in the end of the 80ies, this white painted spars came with the boat from the original Laser boat builder (ergo: not a replica gear). I our days, I would say, such spars are definitely useful for recreational sailing, if they are not already bent and over. 50 Euro or 50 US$ worth for the upper mast segment or boom (if not bent) / 75,- for the lower mast segment, but not much more.
It depends where you are. Australia / NZ have never been supplied with anything other than clear anodised spares, except for a small batch of locally spars anodised black and individuals bringing spars from overseas. Even then from memory, it's mostly been bottom sections.