That hangar looks like it would place the target directly in front of the T post rather than hanging it to the side to be clamped on with the binder clamps. I use a similar style T post hook for my steel plates. If it does hold it away from the post then it could work as a target holder.
If you want to try a steel pipe stand, you could do that. Two elbows, two Tees, two 36-48-60” pieces (depending on how tall you want it), one 24” piece as an crossbar, and four 12-18” pieces make the set. Make a U with the tees at the bottom, Tighten the elbows and Tees tight, then the four short pieces go finger tight as support feet that can be pulled out for flat storage/travel. I use these for cardboard targets as well as hanging steel IPSC torso- silhouettes and it works beautifully.
Stay safe.