I may have an opportunity at a 1950's Winchester Model 12 in the Heavy Duck version. It is in 95% or better condition with a THIRTY-TWO inch solid rib barrel. Did these come with factory sling swivels? How much should I expect to pay?

The one I had did not have sling swivels and I traded it to a pawn shot for a Spanish double they were asking $600 for. Both of us were happy and I had a very nice Arrizabalaga SxS live bird gun.