The KV-107's had, I believe, 600 gal tanks. They are appreciably bigger than the original BVC-107 tanks.
The windows are an interesting issue. The original military version had round windows. The KV-107 in military garb also had round windows. Because the Japanese constitution strictly forbids export of military equipment, the "Civil" KV-107's had square windows, and the present JASDF/JMSDF aircraft will likely never be surpluses outside the country.
I think the "Giveaway" on the tank will be the larger tanks have the dorsal spine on them. The smaller tanks don't. I have a fairly extensive collection of Canadian 107 shots from a book I was researching. I'll see if I can find them. What is the serial of the bird yoru doing?
Tank shots
http://www.myaviation.net/search/photo_search.php?id=00716684
http://www.myaviation.net/search/photo_search.php?id=00227033
http://www.vaq136.com/atsugi/atsugi-064b.jpg
Bryan
Denver