The depth of penetration in the bone shows more towards a lance or atlatl, not an arrow from a bow.

Large game arrow points were very small as a rule.

Remember hearing or possibly having the 'bird' points often found at the buffal drops and reported by the anthropologists? Those 'bird points' are actually large game arrow heads. The small size was necesary for the requisite penetration to the vitals form relatively weak bows. Yes - they were sinew backed, but still relatviely weak & did not have good cast.

Those beautiful points, similar size to the imbedded one shown in the vertebrae are either lance points, perhaps knives, or very large atlatl points, in my opinion. Given the size, they are most certianly not arrow points - it is normal to think they are & is not indicitive of anything negative.