Answer
No — the standard Customer/Supplier Notes fields are genuinely just plain text with no audit trail (no automatic user or timestamp capture) and no automatic surfacing elsewhere in the application. To get notes to actually display when creating a related document (like a Customer Order or Purchase Order), you'd need to build that yourself — for example, a custom field on the order header that pulls in the Customer's or Supplier's note text, or a small custom popup shown at document-creation time that displays the relevant note. There's no built-in equivalent of a full audit-stamped notes/activity feed for these two entities.