Could they be mounted without tubes ?
That depends on who is doing the mounting? If you take your stuff to a shop, they will likely not mount a tire for you tubeless since the manufacturer said they were tube type wheels.
If you do your own work, it's your call, many on this forum have run their tires tubeless for years and countless miles.
For years I have mounted my own tires. Lately(20 years later) I find the task too much for my age or patients/age or a combination of the both.
I tried to set up my R65 tubeless and could not get enough air in the tire to seat the outer bead and inflate. After days struggling with this problem I decided I would just go back to tubes and be done with it.
New problem, I can no longer put the outer bead on the wheel with out puncturing the tube in MULTIPLE places. Carefully I tried again and found the same results...….. so now my tires and tubes go to the shop and I pay. What I get for my money are the two days I would have lost trying to do it myself.
Naturally, YMMV and you will be able to mount tires either tubeless or with tubes in a couple of hours, lots of folks can.
If you do go tubeless and end up out of town on a trip and are forced to go to a shop for repairs, they will not repair your tubeless tire and mount it back on your tubed wheel. Carry a tube with you even if you run tubeless, Many shops no longer carry our size.