That was the smallest model bird that they started to sell in about 1970 and lasted up into the 80's They are smaller than the golden pinto in overall size (there is a golden pinto frame in the far right corner of your photos to compare it to.. looks like it may have remains of the stops for the later centerstand and the open forkplate.
this is a 1979, they were called alot of things over the years but never Wrens