Is it just the glass as I have a dodgy one you can have, the glass is fine but the frame a bit crappy ?
Try on prototype bay forum as I got mine off there, they were fitted to them micro busses all round so more out there
Do what @theBusmonkey said. I took mine out cleaned it up etc put it back and hey presto five years later it leaked again. Putting it back can cause and help the channel to rust. You have jalousies so ventilation shouldn't be a problem. If it's OG you're after you've got the wrong westy sticker anyway......