The Armstrong and Canam are the same beast. Not CCM. As far as I am aware they were only produced as an '84 model. I don't think the year matters for Twinshock unless you plan on riding classic ( I stand to be corrected though!).
Yes they are the same beast. I suspect you may be confusing the 4T CCM with the 2T CCM.
Long story: Cotton married EMC (Eatough Motor Components. Joe Erlich had sued Mike Eatough for copyright infringment) to form Cotton EMX. They won a British MX championship with Pete Mathia onboard. Cotton EMX were then merged with CCM under the Armstrong banner. That is Armstrong shock absorbers. Where EMC bikes had used Sachs motors, Cotton EMX's and Armstrongs used Rotax's.
Prior to the merging of Cotton EMC and CCM Nick Jefferies had developed the Hiro powered trials bike for CCM in the early 80's. This was a separate machine to the BSA powered 4T trials bike that Nick had developed in the '70's. This machine was originally produced as a CCM but, after the merger, was produced as an Armstrong. It's this model pictured above. The CCM differed slightly from the Armstrong.
At this time Can-Am were tiring of the motorcycle market but Jeff Smith convinced them to sell Armstrongs in the US/Canada market as Can-Ams.
The supply of Hiro motors dried up and SWM had gone tits up so the Rotax motor became available for trials bikes (SWM had the exclusive rights to Rotax motors in trials) and Armstrong adopted Rotax motors in their trials bikes as well as their MX bikes. Production of the CCM/Armstrong trials bike stretched from about '82 to about '87.
Armstrong then won a contract to supply the UK MOD with dispatch bikes and this contract took up all their production capacity. Armstrong ceased to make off-road bikes.
Rotax powered twinshock Armstrong
The last Armstrong trials bike (Rotax motor..and Aluminium chassis!! Years ahead of its time)