I'd say it never hurts to ask, but be prepared for a "no".
I would strongly suspect you will have a lot more traction if you are the first part-time employee ever to work for them (or to work in a given role) vs. the 200th. If you are setting the precedent for how a part time person gets paid, you probably have some leeway. If a certain pattern has been set, then changing the pattern is likely to be more expensive in some way than the value of hiring you, specifically, vs. finding someone who doesn't care about the 401K program.
I doubt there are any straight up legal issues of "we simply can't compensate part time people this way", but there could be issues of "if there is a blanket policy for how people are compensated, then you cannot treat people out of alignment with that policy without revising the policy for everyone". There's always a provision for variance in pay (to a point) but it's likely that many companies have written blanket policies of "we give part time people at x hours these Y benefits".