5.2 Magnum Piston Question

No #'s stamped on the crown? They look like a UEM 1266c or a Sealed Power 285np (these are for a earlier 318), which have valve notches. Not a UEM 3234H or Sealed Power H526AP or H814P,for a Magnum, which have no piston notches. Differences also are ; ring thickness, weight, compression distance, cost and no full float pin for the Magnum choice.
They sure look like these, S/P 285ncp's stuffed in a 350 Pontiac.
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