Having been restoring old Mopars for 49 years, having been a parts jobber at one point, a paint rep, and having been trained by a paint manufacturer, and having spent many an hour in a body shop or paint booth, I have the following thoughts.
BC/CC has a very specific look that is different from any single stage paint. It is quite shiny but presents itself in a manner that shows as if the color is underneath a layer,...because it is. If this does not matter to you, then go ahead and enjoy the brilliance that it brings. It is much more resistant to the challenges brought by acidic rain and atmospheric fallout as well as bird poop, etc,. It still requires proper user care.
As an aside, the base coat is usually a water based product, and the clear coat is a catalyzed product requiring specific care and usage (spray) parameters as well as personal protection when sneaking in to the boot to check on the painter's progress!
Single stage (SS) appears as though the color is "on top" and throughout the paint coating (even though there is some separation due to the paint composition) and appears to be "thicker" than BC/CC as a result. Metallic and solid colors can produce superb finishes. Personal protection is required when using and mixing.
SS metallics require care when applying as the metallics can have a run even if the paint coating does not. They can also have a slightly different hue or have a different pattern depending on the air pressure used in the gun, the gauge of nozzle used, the atmospheric conditions when painted and the technique of the painter.
Can they be matched, yes, if careful when doing so.
If your painter has not used SS in a while, it might be wise if he changed his gun to match the SS, and sprayed a few test panels to get back to his full level of quality.
I much prefer the use of SS on an older vehicle and an experienced and patient painter can produce award winning finishes when using it.
As with any paint job, prep and properly matched paint supplies are very important.
Some individuals are of the mindset that polyurethane is the ultimate way to go. Understand that this is an incredibly durable coating, but has very specific needs in order to be used, is very expensive, is usually a solid color blend, and uses stronger chemicals to produce a proper catalyst and panel bond, and has a much more dense look.
Once cured, this stuff is beyond tough to remove and is made to be a maximum strength coating. Be careful and very sure of yourself if this product is your coating of choice. I do not recommend it except for commercial vehicles or items that will receive notable amounts of physical abuse.
So, pick what you like and make whatever you spray look like new. Good luck!
