When issuing a revised LE (due to rate lock or loan amount) is it required to add numerals to the loan ID # ? For example if initial LE was id # 123456, the revised LE should be 123456-01? (or something similar)

I don't believe it's a requirement. We don't. Actually I don't think the practice of it is encouraged. My understanding is that the loan ID should remain the same throughout.

However, I have seen other banks do it.

There is no specific requirement for version identification in the Loan #. You should be able to link the LE's by loan number and Date Issued. Although the guidance doesn't appear to prohibit this type of numbering, I don't see how it would add much and I don't know of any lenders doing this.

From the CFPB Guide
Loan ID #
Loan ID # is the creditor’s loan identification number that may be used by a creditor, consumer, and other parties to identify the transaction. (§ 1026.37(a)(12)) The Loan ID # may contain alpha-numeric characters and must be unique to the particular transaction. The same Loan ID # may not be used for different, but related, loan transactions (such as different loans to the same borrower). When a revised Loan Estimate is issued, the Loan ID # must be sufficient for the purpose of identifying the transaction associated with the initial Loan Estimate. (Comment 37(a)(12)-1)

Thank you for the replies!