Answer:
The requirements for providing the NMLSR IDs of the loan originator organization and the individual loan originator on specific loan documents are found in Regulation Z § 1026.36(g). That information is required on the credit application (once received from the consumer); the loan estimate and closing disclosure required under the TRID requirements of § 1026.19(e) and (f); the note of loan contract; and the security instrument.
Since the TRID disclosure requirements in § 1026.19(e) and (f) don't apply to HELOCs, the HELOC disclosures (pre-application or otherwise) would not have to include the NMLSR ID information.