You got this one dead on as an O-108. It has a rarity rating of 3 (scarce 201-500 known). For others learning to attribute these, the markers are:
Obverse 5: Star 13 is 1/2mm from the curl. There is a fine circular line in the upper loop of the 8, showing that it has been recut and the 18 is noticeably higher than 30. Most show a dot below the date between 8 and 3 near the milling.
Reverse H: 50 C. is rather high with a tall open 5. The left sides of the T and I are in line. Many fine crossbar lines extend far into the right wing. Most specimens show a fine die crack at the top of UNITED.
I believe this coin to be a solid EF45. I believe the clasp strike on this particular variety is weaker. All of the claw detail is strong and all of the feather detail is sharp. A little too much rub to make AU50 to me, but it would probably end up in an AU50 slab.