If we are refinancing a loan and using an existing mortgage, we would put the NMLS# on any NEW documents. Since we are using an existing mortgage, is it ok that it might not have an NMLS# if it has some age to it?

I see nothing in the regulation or its Commentary that would exempt a previously used security instrument from requiring the NMLS number.

(g) Name and NMLSR ID on loan documents. (1) For a consumer credit transaction secured by a dwelling, a loan originator organization must include on the loan documents described in paragraph (g)(2) of this section, whenever each such loan document is provided to a consumer or presented to a consumer for signature, as applicable:

The part to note is whenever it's presented for signature. Since the existing mortgage would not be presented for signature we should be ok to use it in a new transaction. Do you agree?

Yes