S or Fastback

Any Commando with a number like that is early, which means Fastback.

Greg Marshes Site has a good breakdown of codes

https://www.gregmarsh.com/MC/Norton/NortonHome.aspx

This has a good listing of S code specific features as the code is not unique to S types

http://jba.bc.ca/Bushmans%20Carb%20Tuning.html

Good luck!

Eddie

How does the engine 20M3S and "S" the commando model differ?

Is the 20M3S not the beginning of the original "e-start" failed concept?

Is this in any way related to the "S" commando body style? (NO)  Within the series 1 (68-70) rolling chassis commando's, the models "S", MKII fastback, and Roadster all used the 20M3S engine/drive train. All three of these bike model had their own different VIN/SN range.

http://jba.bc.ca/JBCycle/NortonS.htm

Nothing incorrect as I can see and very good, however incomplete! IMO.

Don't forget the 'R'  and 'LR' models which had a limited runs around that time.

"if this is an S type"

1. Verify with published range of vin/SN which only means it is "possibly" original "S" ...Other body styles were shipped within the same range of SN.

2. Verify with factory historical records if it "was" shipped as "S".

My own Commando records suggest that 2M3S 132276 was built before May 1969 but according to Steve Wilson's Norton Motorcycles Book,  the 'S' model production started in September 1969 with 133668.

But he then contradicts this in his year sub-notes by stating that in February 1969 the 750 Mk11 series and first 'S' type commenced production with  Commando 131257.

Another point worth a mention is that 1969 saw the close of Commando engine  production at Plumstead.  These engines from then on being built and delivered from Wolverhampton.  

That number is for an S type Commando 

Sounds like a guy with access to the build records. That's very handy!

Ok, enlighten me ... give that Fastback vs. S-type model differences are just 'skin' jobs and they are both period-correct, why should anyone care how it was built rather than as it is now?

I'd fully agree. This is the most relevant position.

It does not, however, answer the OP question. Only a factory shipment record is somewhat  authoritative on that VIN/SN originality. I show the range of 131257 through 135088 as the period of "possible" "S". Only an itemized record inventory would show which of these were actually shipped as an "S". Anthony has offered the definitive answer.

IMO, The fastback and "S" are certainly the most dissimilar to be in the 68-70 series 1 commando,s. The fastback had at least 2 variants during 68-70.

Agreed that it's not what the OP was asking David, but I am curious. Perhaps the OP can respond about why it matters? I could understand if the question was "is this a Fastback or S-type?" with pictures of the whole bike. Is the concern that it might have left the factory as a Fastback and been converted to an S sometime in the last half-century? Would it matter to you provided it was a faithful conversion? Or for that matter if it was an early Roadster converted to an S by the simple expedient of changing the exhaust?

Because, as we all know. a standard Commando is a state of grace that existed for approximately 3 hours after leaving the showroom.