Yep, I own three different kinds of Sauer & Sohne 32 automatics. The most common one during the Second World War was their Model 38H, which was a double-action pistol with a decocking lever, a feature they still use today. They are popular with collectors, because they were both military and police issue in Germany during the Second World War, and were very good guns too. It was the first kind of pistol I ever bought as a collectors' item, as opposed to a target pistol.
Generally, there is no reason to restrict these guns to low power loads unless they are in really poor condition. Because there are so many old and worn 32 automatics out there, American factory ammo is never loaded "hot". European ammo might be loaded to a slightly higher velocity, but not greatly so.
Sauer was a high quality manufacturer, and German guns were proof tested with special heavy loads, except for some of the guns they were slapping together at the end of the war, or putting together from rejected parts for GI's. So the standard advice applies: if your gun looks rough, or the barrel is really foul, have a gunsmith look at it before firing it at all. That may cost some money, but it's worth it.
You would probably have to have low power loads specially loaded by a handloader anyway, because automatic pistols often don't work well with reduced power loads; they are made for a standard level of power, and may malfunction with less. So ammo makers don't offer them in 32 ACP (at least as far as I know). You don't want to get a bullet stuck in the barrel either, which can happen if the load is too low powered.
People here can tell you more about your gun if you can put up pictures of it, and would probably just enjoy seeing it, anyway!
