The window glass in beetles went through several size changes, there's three windscreen sizes (not including the 1302 / 03), three side window sizes, and three rear window sizes (not counting splits or Ovals), so it's important you get the correct ones.
Genuine VW rubber is moulded to the shape of the glass, aftermarket stuff is formed in a long continous strip, then cut to length and the ends glued together. You'll know if you ordered the genuine VW stuff, because the side window seals come in left hand and right hand, because of the shape of the rubber.
The aftermarket rubber tends to stretch round the corners, let water under the rubber and split in the corners after a few years, although some are better than others.
These guys sell genuine VW rubber -
http://www.status-vw.co.uk
Are you having the problem with all your windows or just certain ones ?
Some of them can be a bit of a stretch to go on the glass, but if your professional says they're too tight, and you trust him, then it looks like you have been sold the wrong ones.
Dave.
