I was raised to never say never, but pythons are not exactly an animal that garners a huge amount of scientific interest so it is not likely. Maybe in some not-to-distant future, when genomic sequencing and analysis becomes as cheap/easy/mundane as computers are now, hobbyists can take on the task.
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The pedant in me would answer that the acts of selective breeding that we engage in would constitute as “genetic modification”. But I am guessing you are asking more along the lines of exogenous gene transfer and CRISPR and the like? I do not know that anyone has ever tried with snakes but there is no reason that the established methods of genetic engineering should not work, genetics is genetics is genetics. They have successfully used CRISPR to mutate anoles.
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Over geologic time frames, sure we could drift them away from being canonical P. regius the same way we drifted dogs away from wolves. However, consider how long humans have been domesticating dogs and they (mostly) still easily back-breed to wolves. So, to all intents and purposes, they will always be P. regius no matter how morphed out we make them.
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Any time 
