>1 - is th GUID the very long hex-looking number in the registry under CLSID?

Yup. GUID stands for Globally Unique ID.

>2 - where is this stored in class (form) definition (VCX) - is it encoded in the OLE field?

It must be, because I can't find it either.

>3 - not sure what you mean by "scroll down to that name to find its other entry" - in this case Calendar Control 8.0 - not sure where you mean to go to

When you know the english name, and not the name of the control (that particular control is MSCAL.Calendar.8), then I know of no other way except to do a search in the registry. Your search will lead you to the "other" entry, which will give you both the ActiveX name and the GUID. Details about the control can be found by looking up the GUID under CLSID\.