Messerschmitt 109E/F canopy Info?

[pstrany]

Hi;
I'm doing a model of the Messerschmitt 109F, and I have a question about the canopy. The main (opening part) canopy is comprised of 6 pieces of plexiglass, two pieces on top, and two on each side. The front piece slides back under the the back piece on both sides and top (I can imagine things must get very drafty if all these windows are slid open at the same time.)

Now my question is this. Where the pieces overlap, some pictures seem to show a dark stripe, while other pictures show only clear plexiglass. Was there a metal strip that ran along the edge of the plexiglass on some models, or is it just that dirt would accumulate there, making it appear that there was a strip of metal there?

Sorry, I know this is really anal, but I like to get the details right. I'll scan and post some pictures showing what I mean wehn I get home.

Thanks!

Paul