Double F - We have sent, easily, 3 dozen, handguns to Robar for coatings.
When I was looking to go against Cane in the .460 Rowland build off, I sent mine off and the results were AMAZING for fit, function and performance.
I think you need to call them. The folks at Robar, and I HAVE talked to them recently, are very knowledgeable about their product and may be able to give you the .000" thickness of their coatings.
I know from SHOT, and talking to them, that NP3+ is an advanced version of NP3. It's rated higher, it has a "deeper" level of penetration and supposedly it's MUCH better for the weapon.
Someone will eventually get a firearm treated with it for FTF and post a review.