The earliest coins minted in 1873 (Half Dollars included), had a 3 in the date that looked like an 8 because the loops of the 3 were so close together. Later in the year, Mint engravers created new dies with corrected 3's.
The 1873 No Arrows, Closed 3 Half Dollar is relatively common compared to other dates from the 1870's, and it is much more common than the Open 3 variant. In addition, this date can be found in high grade. The PCGS CoinFacts Condition Census ranges from a low of MS-64 to a high of MS-65.