Look for this
M/S isn't enough. That being said, my old BFG A/T KOs had that symbol, (not all of their sizes do), and they weren't amazing or anything, in the snow.
When I ran the Goodyear Dura Tracs, I didn't get a chance to run them in snow, but lots of members that have claim that they are excellent. [^ see what I mean

] If you found they weren't good enough, they are pinned for adding studs, but thats not something you would want to take back out, so if they were necessary you'd end up having to get a second set of rims and tires for summer.
One thing that another member and I found out, when we were on a snow and ice covered steep mountain road, was that we kept lossing traction, and spinning the tires even with in 4LO with the rear differentials locked. [He had 37" Toyo M/Ts and I had 34" Nitto Terra Grappler A/T's]. When a Jeep went by that was also running Toyo M/Ts, the other member asked the driver how he was able to do it with no problems, and the same tires. He said to air down. He had beadlocks and was running 5 psi, but told us to try around 12 psi so we wouldn't lose the bead on our normal rims. The difference was amazing! But I would think that even running at 25 psi would be better than, say 35 psi, as long as you kept the speed down.
Here's a link to the 33" diameter LT295/65R18 size of the Dura Tracs for stock.
Discount Tire Direct To cut
through the snow a little better the thinner LT275/70R18 might be a little better.