Interesting question. I'd say we need a skeleton to study to be sure. Measurements, calculation of intermembral index, examination of the skull, pelvis, and ankles .. should tell us pretty decisively. (While we're doing that, lets do some DNA! :))
Size seems to vary somewhat regionally. Given the 2 I've seen, I would say 7 to 7.5 feet would be late juvenile / early adolescent, definitely not an adult. Youth might throw our assumptions about IM index, etc off since they are presumably mostly based on adult sizes.
MIB