That is a fine Grade 2 Magnum 10 you picked up Phil, doesn't appear to have been used hard and then neglected like some we see.
In my experience, most Ithaca Magnum 10's and 12's that I've observed with what appeared to be original pads, they were wearing the Hawkins red pad with the heart shaped vents. I also have a few that I acquired with the Hakins red rifle pad with the straight slots which I just never really cared for and plan to have them switched out.
Just my opinion, but you really need to have a correct pad installed on that lovely Ithaca while letting your shoulder and hand heal
As Dave mentioned, there doesn't seem to be no rhyme or reason as to when cocking indicators were used or not. I have consecutive serial #'s 500,030 and 500,031, both 12 gauge magnums. The gun ending in 30 doesn't have cocking indicators, 31 does. Perhaps customers were asked what their preference was, who knows.
Stan