IMHO Buleprinted has a specific defninition: It is built to the exact specifications and tolerances (or no tolerance) as the orginal designer put in the original design. I have blueprinted car engines many times - and there is lot of work to get parts or modify parts to exact spcification. Same for a firearm. Read up on "Family Porsche" - a Porsche built to exact specification for a memeber of the Porschefamily.. Custom on the other hand is different - it is something new built from the ground up or modified to a one of a kind. Restomod is more of a cleaned up original something with different parts added - such as '57 Nomad wagon with a later model Corvette engine.
The problem with that definition, and that is the common definition, is that everything is set to within factory tolerances. So it is not any better than something right off the showroom floor because all of those parts are also within factory tols or it would not have made it far enough to be sold (excepting the parts that slipped by). This is true of both vehicles and rifles. So "Blueprinted" sounds good, but it really doesn't tell me anything new. OTOH if a rifle is being sold with an action that has been "trued and tuned", now that tells me something useful.
In my whole 30-odd year career in manufacturing and Engineering I can recall seeing Basic dims on three different drawings. Not that the whole part was Basic, just one or more of the dims on the drawing. Which is to say that a part with a dimension that has no tolerance (aka "Basic") is a pretty rare thing indeed. Mfr's do not like them, they drive the cost of the part literally astronomically high.
I do cars more than rifles, Restomod is a very familiar term. One that I think should be applied far more often than it is. When I see something like a '57 Nomad with an LS3 in it and the seller is calling it "Restored" I immediately figure they're either lazy, ill-informed, a shyster, or a used car salesman; and possibly all four. When they label the same car as a Restomod then I think that they're being much more truthful and are likely much more engaged in the car hobby.
"Custom" could be defined as I changed one action screw from blued to stainless. That makes the rifle truly one of a kind as there aren't likely to be any others out there with only one SST action screw. So calling a rifle "Custom" means nothing, but it sure sounds good!