Currently the syntax of the CUIT is not curated. The Golden Record, the Curated Record and the Augmented Record should however provide the official syntax. The AR.NRC provides the identifier without hyphen but the official syntax is nn-nnnnnnnn-n.
Also see:
In the Golden Record both, the original value as well as the curated value should be shown. This allows e.g. SAP users to select the value without special characters (especially relevant for some sharing members in regards to CH_UID / CH_VAT_ID).
Also see: https://meta.cdq.com/Identifier_format_invalid_(CUIT_number_(Argentina))