In my book, a "rebuild" means modification (grind, rebore, etc.) of major parts due to wear: crank journals, bearings, cylinder bore, etc. A valve job is not a rebuild, nor is the replacement of individual broken parts. If you went through an engine and removed carbon, adjusted shims, changed the gaskets, but didn't replace or re-grind anything, that's more like a tune-up or inspection.
All of which is to say, if the major moving parts are still factory standard sizes, it hasn't been rebuilt (or it has been restored, which is different). If they're not, then it has.