No. It is not necessary to set targets for all indicators. As noted in the EC Guidance document on Monitoring and Evaluation, quantified targets “shall be set for a limited number of common and or programme-specific indicators at the level of investment priority and category of region. Limited means in this context that not all indicators need to be linked with a target value”. The only exceptions are the YEI result indicators (both immediate and longer-term) all of which are required to have associated targets.
In general, it is up to managing authorities to select the indicators against which to set targets, based on their relevance to the objectives of the programme. If programme-specific indicators are used, it is possible that targets are applied only to these and not to any of the common output or result indicators.