depends on your country>>7458132
you're flat out wrong, you can do whatever the fuck you want to your toy gun, up to and including turning it into a real gun, providing you follow applicable laws such as the 1934 NFA.
to be imported into the US, they must have an orange tip, that's what you're thinking of>if try to shoot a scene in public you will get the police called on you and they will not ask questions first
this part is true, toy guns get you shot by police and zealous zimmermans. they are stupid to play with, and stupider to modify to look more real
that said, use a dremel, and you'll probably need a coat of paint afterwards, although really those aren't bad
seriously, nobody knows anything about guns, see this thread for an example, and that means nobody would know the real version of that gun doesn't actually have the markings you want to remove. it's kind of a waste of time, in my opinion.