Jannik23,
In theory, there is a speed protection mode with V/S on the B737Classic/NG, but in reality, as Denti said, it is not to be trusted on the B737 Classic.
If you fly the Classic, you will no doubt know that it has a very weak autopilot system and that it gives you "surprises" from time to time, especially related to speed. Be aware of that, anticipate it and you'll be fine.