Oil bath air cleaners were available on the light-duty '60-'66 Chevy/GMC trucks, and more commonly found on the HD Series trucks, ie, C50, C60 & C80. I have had a few and they don't have a seperat filter, just the serrated cage with coarse steel wool/mesh as the filtering media.
I don't currently have one, but I see them from time-to-time on eBay.
