DDK - Die Deutschen Klassiker

I've followed the previous postings re tubeless rims having safety beads and tubed rims not but I've now got a few '69 5.5 * 15 911 steels with only one safety bead on the outside of the rim.

So, does anyone know whether these rims were intended to be run with or without tubes?

I'm assuming the original thinking was that your only really likely to get sideways knocks and loads on the outside.

I've also got some later '84 944 steels which have two safety beads so these are obviously tubeless.

thanks
Andrew