The Ron Sessions T-400 reference calls for .003 - .019 rear end-play. On my 400 I found .030 during disassembly.
As you probably already know, selective thrust washers can be had to make up the difference, you have to mike the selective washer you have after removing the planetary gear assembly from the case.
I wouldn't imagine the 350 would be much different than a 400, at least on the point of having/not having or requiring a certain amount of end-play.