Since you have a similar unit to mine, I presume it is the Carefree Travel'r awning. The pitch pin is a part that can be purchased if you prefer to have the pitch to lock using the Valco spring button versus hitch pin.
This is the manual on my Travel'r:
https://www.carefreeofcolorado.com/d...ice-Manual.pdf
Page 9 contains the detail on the pitch pin replacement.
The round top of the pitch pin is to aide in the retraction of the pin for adjustment. A pin in good condition will have full extension to "pin" the arm into position.
Bobby