I have a C2A1 dewat. I am not sure you are thinking about mine because I have never offered it for sale. It was for sale as a full auto on the EE for a while, and when nobody jumped at it, I purchased it and had it transferred to a local dealer liscenced for that class of gun. The deactivation was done there. My conscience did not sit well with deactivating that gun, it was a beautiful example. I am sure I have condemned myself to H-E-double-L for that one.
I also have the C1A1 dewat. Most of these are the ex-OPP guns that collectors source brought in. Their value ran from a low of $750 to a high of $1600. I hope to ad a non-8L gun to my collection one day. I have also managed to find a dewat SMGC1
The FNs, along with the SMGs, were available to DCRA shooters way back when, and as you mentioned, there are many of them still in private hands here in Canada. I think the number of C1s numbered in the 300 range, while the C2s were in the half dozen range.
It is also my understanding that a number of C2 receivers (and likely C1 receivers as well) were sold off when CAL closed it's doors. Many of these were passed around in the collectors circles and had been assembled in to guns. One of our local full auto guys lost his when he re-registered it as a 12.5 in the mid 90s. The RCMP sayed it was a C/A, and he argued that it was not since the receiver left the factory as a non-full auto. He lost.
There are also many C1/C2 wannabes on the market, built up on everything from Ishapores to Lithgow receivers. There are even some C2s built on C1 receivers. To find a legit C2A1 is kind of tough, since the numbers released to full auto guys was not high, verses the (non-restricted at the time) sales of the C1s.
The Canadian Forces stocks of these guns have now been completely smelted. I was talking to a guy in the know a few days ago who mentioned 250 of each were saved for museums, and future research purposes, and that all parts stock was also unable to be sold to the civilian market. In fact, even the Unertl scopes from the C3 rifles are destined for the crusher, due to their mil-dot specs.