Some 1971-S proof pieces (and a few uncirculated 1971-S) have the serifs at the foot of the "R" in "LIBERTY" missing; this is dubbed the "peg leg" variety. The serifs are missing on all 1972-S, both uncirculated and proof. After the Mint obtained better steel for dies, the serifs returned for all of the remaining non-Bicentennial coinage, from all mints, though the leg of the R was shortened, and also for the Type II Bicentennial (the Type I lacks serifs on the R). Gasparro was often trying to improve the detail of Eisenhower's head during the coin's tenure, and as the R is the letter closest to it, these changes were most likely made in an effort to improve the flow of metal as the coins were struck.