How can I tell whether a model may be operated in Europe?

By the EU declaration of conformity – not by the CE sticker and not by the product brochure.

Steps to check: Is there a declaration of conformity for exactly this model? Which legal acts does it name? Is machinery legislation included? Are there test reports for the radio modules according to European standards? Is the battery certified according to European requirements? Is there an operating manual in German?

If one of these points is missing, that is not an exclusion criterion – but it shifts effort and responsibility to you or to your supplier. The complete checklist is in guide to CE conformity.