Anyone can help me out to get a factory radio code? Please help!!!!

I just bought a 1991 Mercedes 190E 2.3, this radio is made by Alpine

I tried dealer to get the code with VIN # WDBDA28D7MF736193, but 2 dealers guys told me that radio is no code

I took off the radio today!!! It is made by Alpine (Model number CM2190)

S/No. AL 2190Y0221158 (B00221158A)

OE radio parts # is 002 820 75 86

Anyone has radio unlock program and can help me to search a radio code? Thanks