I think it's either a damaged D, or a die chipped or filled D.
I'm not aware of any RPMs for Philly Quarters in that decade, there are Denvers though.
Also this is the wrong MM style "P" for the date, it should be MMS-002 and looks nothing like it.
http://varietyvista.com/09b%20WQ%20...20Styles.htm
they phase out handpunching mintmarks on dies completely by 1991, Philly was already adding them to their master dies long before the other mints.
I'm not aware of any RPMs for Philly Quarters in that decade, there are Denvers though.
Also this is the wrong MM style "P" for the date, it should be MMS-002 and looks nothing like it.
http://varietyvista.com/09b%20WQ%20...20Styles.htm
they phase out handpunching mintmarks on dies completely by 1991, Philly was already adding them to their master dies long before the other mints.



























