I went to this site
https://fordcommercialvehiclecenter.com/ and set the filters at the top to 'f550' and 'motorhome', luckily it shows a service center about 7miles from my home (which is across from another RV center)... Seems legit, I'll call and confirm, but it did eliminate the two ford commercial service centers nearer to me...
The location I made the deal for the rb34 appears to be the only authorized dealer in NJ (only one linked in Thor's site)... and I believe they stated they are an authorized service center for Thor'...