Well, the Ju-52 DOES have a built-in, fully functional heading hold gyropilot. That’s ALL it does, as it can only control the rudder in very small deflection. While you can change the heading bug and it will follow it, the turn radius is like 5 miles so this is only practical for en route turns of up to about 10^. For all others, you need to turn it off, make the turn yourself, adjust the heading bug once on the new course, and turn it on again.
As for altitude hold, there is none. HOWEVER, since the last update, the plane trims out so well you don’t need one, at least in relatively smooth air. But I’ve flown the Ju-52 all over even at 4x time warp and the altitude hasn’t changed enough to notice. And, of course, it’s held the heading, too.