There are two schools of thought on the Sekine serial numbers. Regardless, it is mid-1970s, either 1975 or 1976. Personally, I'm leaning towards the latter. In 1975 I was managing an LBS that carried Sekine and they had a beautiful dark red which they called Burnt Red . However, I don't recall this model coming in that colour and a quick look at my old literature confirms my memory

It's not one of the Canadian manufactured frames but a Japanese manufactured frame. However, it would have been assembled in Canada. The model is an SHC 270. FYI, the crankset may be the infamous SR Silver. If so, this crankset did not use a spindle with the standard 2 degree taper but one with 3 degree taper and it is harder to find replacements. .