On a card whose left and right borders add up to 6 mm, 52/48 centering means a 3.1 mm border on one side and 2.9 mm on the other, a difference of 0.2 mm. That's invisible to the eye.
Questions
Can a 52/48 card get a PSA 10?
Yes, on centering. 52/48 is inside PSA's 55/45 front limit for a Gem Mint 10, so corners, edges and surface decide the grade.
Is 52/48 good centering?
52/48 is gem-level centering. It's inside the 55/45 front limit for a PSA 10 and a CGC Gem Mint 10, so centering won't hold the card back.