I'm also leaning toward it being a Canadian bottle. The only thing I have been able to come up with so far is that at one time there was a Kelowna Bottling Works located in British Columbia. But even if the K does stand for Kelowna, I'm not sure what the F B stands for. My best guess at the moment is ...
Needs more research but maybe Kakabeka Falls Brewing Co Ltd., Fort Williams, Ontario
From 1925 bottlers guide. I may have been changed to Bottling at some point during prohibition also. [8|]