Barry,
This is from the fellow that had this pennant framed, "Please keep it in the frame as it is, as there is no stitching, glue, etc... holding it in place, but rather is held there by a museum quality acid free plastic envelope. All of the matting is acid free as well. They actually call it "elvelop" or something like that."
The baggie really stands out with a flash. But, isn't as obtrusive in real life. It's not glossy either. And the double matte helps keep the pennant away from the glass. Doubtful I'd have it framed differently.
