Is is custom work over the factory orange? Vibrance was a custom paint line which will make matching it next to impossible even if it was sprayed by Harley. Even if you had the pearl you would have to do a lot of testing to get the mix and amount of coats right.
Most motorcycle manufacturers keep the paint codes as proprietary so they can sell you whatever crappy paint they sell at the dealership or buy a new pre-painted part. Harley is the worst for that. That being said matching the orange won't be that hard. Local Paint Jobber should have the Color camera to take a picture of and analyze the color for the closest match in their library. All the majors like PPG, Axalta, BASF, have this camera.
As for the pearl I would first check with PPG and ask them if they have any recommendations on what to substitute the Vibrance pearl with. Quite possibly they have a match or substitute in their newer custom paint line. Best way to do this is go to the local PPG Jobber and ask them for the contact info for the area PPG Technical Rep. Don't ask the Jobbers themselves as they will have no clue usually. Get the area tech rep's info.
If they can't give you any info you may want to inform your customer that you would have to redo all the pearl on the bike.
Maybe Jim C can tell you something different. He does a lot of motorcyle and custom paint work, more than myself by far.