Neither is necessary and I did neither. But if you feel it's necessary, set the dethatcher tines to nick the soil (set them low, in other words), and call it a day. You really don't want to dig into the soil and throw the stuff around right before seeding. You'll bury all the weed seeds sitting around at just the right depths as well. It'll be the start of a Really Bad Couple of Weeks.

For us novices, what’s “tttr”?

I presumed he either meant turf-type rye, or mistyped turf-type tall fescue. Turf-type rye really isn't a thing, per se, it's perennial rye, although some modern cultivars practically deserve a pretty name all their own with as nice as they are.

Thank you and yup that was my bad. Tttf, I have fescue