How do I confirm this SL is real?

[luvmy84300sd]

Hey SL Fans,
I have the opportunity to finally purchase an SL at a reasonable price. It is a 1977 450 SL - European version (square headlights w/wipers & washer sprayer, short bumpers, etc.). Is there any way to confirm (other than the appearance) that this truly is the Euopean version?

Also, the original radio is now missing...was this a Becker Europa? Does it have to come from a 1977 or is this the same from the 280 SL?

Thanks for your help!! & wish me luck!!!!!