Chouinard Thick Horizontal piton c.1959 I have seen a few others of this piton. Since it appears to be not so well crafted, I consider it a junk piton. Maybe it wasn't coming out correct so it was thrown to the side.
Chouinard pitons shown in the March 1960 Dolt catalog
Chouinard Lost Arrow progression
Chouinard 1958 Horizontal piton YC Collection
Chouinard Horizontal pitons c.1957/1958
--- Sometime between 1960 and 1963, the "Lost Arrow" name was given to the pitons
Info tag shows 1966, but I believe these were made 1962/1963. YC Collection
Lost Arrow - 1965 Chouinard catalog
Lost Arrow - Chouinard 1967 catalog
Chouinard Lost Arrow Wedge - 1975 Camp/Interalp
Patagonia corporate. Outrageous Achievement (1989 and 1990) Lost Arrow given to amazing employees!