not sure about age of canadian coca cola hobbleskirt that i found no date on bottom

[RCO]

found this swimming on Friday , not at location where I have been finding lots of bottles but at another set of docks in lake of bays area that I previously went to last summer and found a number of coca cola bottles from 1940's era but this one seems to be a bit older , no date on bottom but bottle itself looks the same as others I have found . bottom only has a D in triangle and a number 1 . my guess is its from late 20's early 30's maybe but not sure

 

[cowseatmaize]

I was thinking the clear were wartime Cokes but I seam to remember some in the 70's also.Sorry, no help I guess, just typing out loud.