I would agree with Elizabeth, that the addition of sensory processing/sensory defensiveness to rigidity and anxiety does make additional eval for ASD more advisable. The GARS-3 is a decent indirect instrument for ASD; I use it myself, and find it informative. It does not, however, replace direct assessment by an experienced multi-disciplinary team using the ADOS-2 (it should be a team of specialists, including, preferably, psych, speech/language, and OT (or at least psych and one of the others), and not an individual).
And, BTW, Matrix Reasoning isn't exactly a measure of social perception, although individuals with deficits in social perception may also score poorly on it, possibly because of the fluidity of social situations, and possibly because individuals with perceptual weaknesses often have difficulty with reading facial expressions and body language (but this is distinct from weaknesses in theory of mind and social perspective taking).
If you're not sure where to start looking for an autism specialist, you may have an NICHD autism research center or autism center of excellence site in your area somewhere. Check "current sites", and also try googling "autism center of excellence" in your area, as some of the centers are not engaged in current research projects (and thus not listed on the site), but still have many resources:
https://www.nichd.nih.gov/research/supported/Pages/ace.aspx#currentIf you happen to be in the Northeast, there's the National Autism Center:
http://www.nationalautismcenter.org/Also, check your regional Children's Hospital.
