Google thinks the geoloc is 25882 Vicar Way, Lake Forest, CA 92630 which sure looks like a business operating out of a residence to me.
23122 El Toro Rd. Lake Forest, CA 92630 does look like an industrial park location that could service customers with appointments.
My impression, formed by web searches, is that they are legit, will strive to describe instruments accurately, will do things their way (non-FedEx shipping might not be negotiable) and are not a place for bargain shoppers.
I'm not finding Sunspot Guitars on Reverb.
It looks like rareguitargallery.com was registered on 2019-10-28.
I'm guessing we are looking at an evolving business.