Spaghetti sword & sandels, like spaghetti westerns, films were mostly Italian production films (money backed) with international actors, who worked cheaper. A lot of young unknown actors starting out in their career (Clint Eastwood for example) or has been actors trying for a comeback/paycheck played in them. A lot of those spaghetti flicks were shot in southern Spain. Why dubbed? Because most of those cheap productions had each actor speak in their own language when their lines were delivered and redubbed at the editing studios in (usually) Rome. I'm assuming that was also cheaper to get the shoots on film as quickly as possible and do the finishing up at the main lot in Rome. Location shoots were big money and it 's all about profit, then and now. No union than, so the studios could hire and fire at will. And have actors work way below scale. Dont know if Reeves did his own dubbing . In any case, not a guy borned to be an actor. He stepped in a pile of luck somehow, I guess, to get those movies.
Reeves was 20 to 30 lbs lighter for all his movies. The public was not ready for a truly muscular big man at that time (late 50's to early 60's). Or so the studios thought. I think they were mistaken about that though, Reg Park did well.. Don't know if anyone has seen "Don't Go Near The Water" (probably mid 60's) but Dave Drapper was not a bad actor in that flick. Larry Scott had a few background shots. Some people around that time thought that Drapper should have had the Conan role before Arnold got it. As far as Spaghetti S&S or westerns go, I've heard they was a lot of sex and drinking on those shoots, mostly off camera. Everyone was banging everyone else. Low pay but benefits none the less for some of the the actors and crew. Good Luck.