Barrels made with reasonable care will regulate reasonably well. Better than "reasonably well" is expensive. So, only guns with a profit margin that allows expensive hand work will be hand regulated. That said, only the top Original Quality grades would be subject to such work. Average grades of anyones guns would not be hand regulated.

"Shot and regulated" is basically an assurance from the selling brand that a gun from a less well respected brand will perform to the seller's reputation.