Put the seal in, but forget the needle bearing "up grade". Ford only did it one year, 36?, then back to bushings. Needle bearings need to roll, not just sit in one spot, like driving down the road straight. They will eventually make a wear mark on the sector shaft and ruin it. Bushings can be replaced as needed without wrecking the shaft
The logic expressed above regarding bearings and grease seals isn't exactly bullet proof. The bearings need lubricant, of course, as do the bushings, but if that lubricant isn't present as suggested, why bother with the grease seal? Further, given Ford's cost consciousness, why would they bother using roughly a million of bearing-equipped sector housings in late '35-'36?