These come in and out easy - couple screws on top and the nut on the bottom. Even easier if you have the whole assembly out of the door. Saves your arm skin
Sounds like you are referring to the frame they go in though. I haven't removed the "flag" from the "pole" (best description I can think of) but I believe it's riveted on so could be removed/replaced if one really wanted to.
Same goes for the top pivot point on the actual glass frame (what is in the ebay listing). I removed mine to powdercoat them and bought some special shouldered rivets to reinstall.
Scott
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Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole
But there ain't nothin' wrong with the radio