Without cutting the whole front of the cab off and swapping it with a 54, not a chance. There are a number of people who sell one piece "bent" windshields for these trucks. Check ebay,
http://cgi.ebay.com/ebaymotors/1947...yZ80740QQihZ018QQitemZ280129776426QQrdZ1 Personally, I like the division bar, it's an old truck and that reminds me.
As far as not leaking, don't bet on it. First off, you are using an aftermarket part, one that is a modified version of orig no less. That in it's self tells me you will have problems. But really, when you bought a new truck in 1950, the window didn't leak! Sooooooo, that tells me that with new GOOD rubber, properly installed yours won't leak in 2007.
Brian