Remington 48 Slug Barrel?

Wondered if any of you Remington experts out there could answer this:

I am under the assumption that Remington produced a 'Rifled Slug Special' barrel for their Model 48 (I have seen some where individuals had put on their own rifled sights, but, I am interested in the real thing). Does anyone know if they actually did or not? Further, assuming they did, are these extremely scarce?

Thanks in advance!