LOL... it's easy to feel bad about the question, but there are no dumb questions so don't worry about it! You were able to find out something about your truck you didn't know you had. Those free feature finds are GREAT especially ones that save you money!
On the same token I love those mirrors that extend when needed and retract when not needed, just as I have on my truck and am happy for you that you have them, too.
On my Ford there are two mirrors but the second blindspot mirror is positioned to see my rear tires (helps with parking, towing and curbs) so I added large round C-Betr convex mirrors that attach in the gap between the large side mirrors and the door. While this makes a lot of mirrors to look at, the side and rear visibility is great. The C-Betr is so large and convex I can actually see the top of the trailer when towing along with side traffic right next to me. Unfortunately, I don't think they are available to all truck mirrors. However, here's the link and maybe it could give you an idea how to retrofit this design for your side mirror configuration:
http://qwks.com/C-Betr-Mirror-Set-p-3.html