Blueprinting... Educate the uneducated
So just going back to factory specs and then from there you bore it, then "deck and centerline?" (what ever that means)
In effect, it means to bring it to a 'tighter tolerance' than factory. The factories would use anything that got cars out of the building, regardless of if it was 'to spec'. Even if it was 'to spec', it often meant that you'd have pistons of different diameters, cylinders with different strokes, valves with different lash or preload. But so long as it was within the allowable range (ish) it shipped. Blueprinting tries to make everything precise and the same.
Decking has to do with squaring the cylinder head surfaces to the crank axis. Centerlining is to ensure that the center of the bores intersect the centerline of the crank. This is often called 'align boring' also. Boring is the machining of the cylinder bores, and honing is the finishing step that does the last few .0001" worth of work and gives a smooth surface for the rings to run on and also hold oil. The idea is for the block to have a straight main-bearing bore/axis, with bores spaced properly and whose centers are exactly over (or properly space from) the mains axis, and decks which are parallel to the mains and perpendicular to the bores. This cuts down on cylinder-to-cylinder differences and makes an assembly much closer to 'perfect'.
If the engine/block has had that kind of work done, there should be a sheet from the machine shop which lists the final measurements (before AND after if the shop is actually decent). There are ways to verify these things if you're handy with measuring devices (dial indicators, calipers, at a minimum) but unless they're verified it's all smoke and mirrors. Cheap shops will just indicate off what's there, or off what's convenient and not always achieve 'perfect', let alone 'better'. We're also talking corrections which can be measured in thicknesses of paper or widths of a hair (literally) - so it can be tough to visually see.