Yes, your reading is correct. It belonged to a person named Theodoros who held the rank of patrikios. The
legend is phrased in a dative (theodoro), not a
genitive (theodorou), which is a development that took place in the late 7th and typically in the course of the 8th century, the time of
iconoclasm, when these invocative
monograms with legends in the quadrants start to appear, and of which you posted a nice example. So I would date your seal in the first half of the 8th century. There is no way to be sure these belonged to the same individual. The name of Theodoros and the rank of patrikios are both very common on
seals.
Regards
Gert