Yes, such implementation differences definitely exist!
Whether one emphasizes the differences or commonalities of Prolog and Datalog may also depend on commercial interests: For vendors of Datalog systems, it may be advantageous to stress the differences. For Prolog vendors, it may conversely be advantageous to stress their commonalities.
Personally, I learned Prolog before Datalog, and it was easy for me to learn Datalog because I was already familiar with Prolog. The reason may be that I try to write as declaratively as possible when programming in Prolog, and that carried over well to Datalog too. More recently, I have also used tabling in many Prolog programs, and often obtained very general programs with good termination properties, similar to Datalog definitions.
Whether one emphasizes the differences or commonalities of Prolog and Datalog may also depend on commercial interests: For vendors of Datalog systems, it may be advantageous to stress the differences. For Prolog vendors, it may conversely be advantageous to stress their commonalities.
Personally, I learned Prolog before Datalog, and it was easy for me to learn Datalog because I was already familiar with Prolog. The reason may be that I try to write as declaratively as possible when programming in Prolog, and that carried over well to Datalog too. More recently, I have also used tabling in many Prolog programs, and often obtained very general programs with good termination properties, similar to Datalog definitions.