Are 360 frames individually numbered?

So I noticed on my car a number on the left hand side frame rail in the engine bay just behind the thermo-coupler ecu. I don't have a picture of it handy but found a picture from a car sold by Ferraris online (it looks like the number for that car is 115) https://ferraris-online.com/cars/2000-ferrari-360-challenge-n-gt-119339/#gallery-17. My question, does anybody know what the number signifies? Is it on all 360's?

 

Negative, this is a second number that is closer to the fire wall on the frame rail and actually stamped into the frame rail itself and not a plate that is riveted into the frame rail. Both numbers are present on my car. The assembly number for the car linked in my first post is 36397 and the stamped in number (frame number?) looks like 115.

 

Here is a closer look at the number in question.
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Maybe I should start with the question, Has anybody even seen this stamped number on their 360? I have seen it on 3 cars so far. Mine (a 99 US model) a friends (a 99 Euro model from the German market) and the one pictured above.