Pedantic, bit it's a 380SL. The letters, numbering, and vehicle quality didn't change until the 90s.
Honestly, I would worry too much about radio theft anymore. It's not the 80s
You have a few options. To be honest, if you want an OE look but with features, there's a Continental head unit floating around that matches the look without annoying disco lights.
You could also spend cash on a period correct Becker unit and replace the speakers. However, these radios absolutely suck in quality. Becker Auto Sound has a service where they will supposedly "upgrade" the unit with Bluetooth and an amp output. I don't know how good they are and it's really costly ($500).
I went el cheapo with a Bluetooth CD player head unit and 2 drop in 4.5inch speakers I got from Walmart on clearance.
Anything you get over stock is an upgrade even if you cheap out. The quality difference is immense. Top down driving and music blaring is great.
Guess the better question Is what is your budget?