Based on my research into the 300SL / SL320, the 95 E320 is still going to be pretty basic. The 95 M104 6 cylinder has electronic fuel injection over the older CIS system.

The car needs to go to a shop / dealer for a pre purchase inspection regardless what the current owner says about condition. There are times when a owner just doesn't know the real condition of the car.

The car is nearly 20 years old so don't expect it to be perfect or not needing some preemptive repairs. In fact, preemptive repairs will allow you to enjoy the car through the summer rather than having things break at random. ( coolant hoses, belts, battery, filters , brakes and such )