It has to be one of the API symbols. See pic attached. Most Heavy Duty Engine Oils (HDEO) do not contain friction modifiers, as fuel economy is not the foremost concern. And yes the new Rotella T Syn 5w-50 meets the JASO MA spec due to lower ash content. I would not get too hung up on oil ratings, go by real world results, and many members here have used Rotella T products with great results. The more important thing is to pick a viscosity that suits your climate and riding style.
There are so many brands of oils that will work satisfactorily, that it comes down to personal preference. If you have been happy using Mobil 1 in the past, there is no reason to not continue using it. Same with Rotella, Amsoil, Motul, Repsol, Yamalube, Castrol, etc. Modern oils are good, so use what makes you feel comfortable.