Well, slight correction. I suppose it's not uniformly replaceable in all Qs. This website seems to indicate later production models have the part integrated into the hose: https://www.infinitipartsdeal.com/parts ... ?PNC=47210
Either way, both can work with a discrete check valve (I don't see why not), and 47478-6P100 is the original part number. It has been superseded but should still be available at some dealers.
The other option is grabbing any check valve off the shelf that fits the tubes, but I'd rather stick to a properly designed and sized unit.
Of course, test the thing first so you don't waste time/money on an unnecessary replacement.