It looks like you have a Super Riter model to me, but I would have pegged it as being a mid-'50s to early-'60s model based on its looks.
 
I assumed that you used the American-made serial number list to come up with 1945? If you look - as an example - at the list of serial numbers for machines made in England you'll see that their serial numbers (post 1952) are much lower; I suspect that it’s a similar case for machines made in Canada.

The 'C' prefix does mean Canadian made, at least that's what I've been able to determine based on the serial numbers of my Remington machines. Each one that I own that was built in Canada uses the 'C' prefix, just as every model I have that was built in England has an 'E' prefix. 

I've had a few issues dating my Canadian-made Remington models because the numbers never really matched or made sense with those posted on the Database. I suspect what’s missing is an additional list of Canadian serial numbers, one that unfortunately hasn't been published as of yet (at least not that I’ve found). Given that there are English, Dutch and French number lists, my theory makes a lot of sense. 

I’d bet that you would be closer to the date of your machine's manufacture if you used the England-made list instead. I could be way off on all of this, but that’s what all my investigations to date on this subject have left me to conclude.
 

Nope, not English-made !  The shape and colour of the keytops would be different if it was (would be dark green and the same style as the surrounding control keys).  My vote is for a later machine because of the silver paint.  Earlier ones (at least the English model) had grey crackle finish paint.

By the long arm of coincidence, I picked one of these up from a customer today for repair.  It is a grey crackle finish Super Riter from 1954.  On the back, it has a transfer that says 'Made in Great Britain', which would of course include Scotland, and the serial number has an SJ prefix.  I couldn't swear to it, but I think the previous KMC model had the EJ prefix (or at least the ones I saw did)

The 'Super Riter' brand name was used on several machines. The designation of this machine is an SJ, but like most manufacturers, they often released a model under different names with variations. For exmaple: The SJ model was sold under the names 'Super-riter', 'Master-riter' and 'Rembrant'. 

From what I can tell, the UK machines resumed a SJ designation and dropped the E at some stage. But the earliest had E designations. 

The C is certainly curious. I'm with you Uwe about the location of manufacture. We just need to find some other Canadan made machines with a C in the serial to prove it. But I'm sticking by my 1963 manufacture period. 

Just for reference, the French made super-riters had the prefix 'JF'. And the dutch version had nothing. 

CJ657165 I'm going to guess is probably 1952 ?

From Schramm 1962 (in German):
###############################
Remington (Kanada)
CX 44 001 u. darüber - 1940
CX 62 000 - CX 767 399 - 1947-1953

They're vague about specific years, but you can mentally run an algorythm to extrapolate ranges between 1947 to 1953 and 657165 is at the tail end of that range.
(the "X" probably indicates that all canadian models ran in the same number range. The "C" prefix seems to have been used for all Canadian-made models except some Canadian Noiseless models from 1940 through at least 1954.)