Seems fine. Again, please verify that your gas cap is the vented version. If not, you can drill a tiny hole and make it vented. Without that you will build a vacuum in the tank until the engine shuts off.
On some other brands of transmissions it is possible to add synchronizers to un-synchronized gears, but not on MB units. Such is life. It's easy enough to live with though. The good news is you don't have to fix anything.