Lafranconi exhaust question

[Mtoliva]

I have a nice pair of Lafranconi’s , but they have slightly different serial numbers, one ends S/C and other only S, can anyone tell me why ?

 

[The Sock]

Is the left one ‘S’?
Sinistri is Italian for left.

 

[Paul Marx]

Is the left one ‘S’?
Sinistri is Italian for left.

Sinistro in the singular.
To keep to the Spanish theme like the Jota, maybe the C is for Cojones?
Paul

 

[IAG]

Sinistro in the singular.
To keep to the Spanish theme like the Jota, maybe the C is for Cojones?
Paul

So 'S/C' translates to 'Left Nut'?

 

[CLEMTOG]

S = standard
SC = sport competition.
???
CLEM