The term 'neurotypical' is quite relative. For example, synaesthetes might think of themselves as ND or not-NT and those without synaesthesia as NT.
Or the term can be used for anyone who has no neurological conditions.
Relative to Asperger syndrome or ASDs where those with an ASD are ND and those without an ASD are NT, then yes an NT can have synaesthesia.
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I don't have Aspergers, I'm just socially inept
Dodgy circuitry! Diagnosed: Tourette syndrome. Suspected: auditory processing disorder, synaesthesia. Also: social and organisation problems. Heteroromantic asexual (though still exploring)