On my el camino I didn't need to (plenty of things to keep it in place). I can see how it would benefit though. Is there anything to tuck it up against? If so, you may be able to drop a piece of pinch weld in there.... I did that on the door posts with my tweed...
If you need to hem it - then MAKE DARN sure everything fits perfect before you hem - otherwise it will not line up correctly.
- Ryan
