No - they won't be confused. The big difference is, that with autism, there is are difficulties with social development. Early on, in young children, this will show up in play.
But you really need to know quite a bit about play development to spot it. Non autistics will usually create 'play scenes' when playing alone - so, for a boy playing with vehicles, a very bright boy would create an extended imaginative story - you might have him picking up passengers, going through a magic barrier and into a fantasy land- the imagination is rich.
With autism - play is more focused on the mechanics of how the wheels move, the technical specifications of the cars, very fact based, not story based.
When playing with others, a non autistic child round about 4 years will be pretty advanced in very complex play - you will see the kids discussing together how it will go, problem solving, comforting upset children, etc etc.
And very bright non autistics - they still play imaginatively. If they are true genius level, you might observe their thinking is ahead of the other kids and, in time, they prefer to play with older kids. But they all play. Imaginative games.
Autistic children don't play as well. They have difficulties fitting in with other kids and they often want to control the play - which causes upset.
Or - they don't do imaginative play - chess is an example of non imaginative play. It is rule-bound which suits an autistic mind.
Autistic minds sometimes prefer non fiction or fantasy world type books.
They like technical facts and figures.
As many boys do like this sort of stuff, it can be quite hard to spot high functioning autism at certain ages. It might be less apparent during the primary years - but be more obvious again at high school.
Typically, high functioning autism during teens might be showing lots of success in maths and sciences, seeming very consciencious but not going out partying, drinking, having romantic relationships (maybe online only)
It's the social development. That is where the big difference is.