Good morning Nalla,
Everything involved with the previous experience and testing of the exams would entail all information needed for a person with a CWI or SCWI to show ability to perform Dimensional Examinations as well. In many ways, that is indeed a part of an inspectors job and especially if it is written into the Contract or Employment Documents/Job Description.
Now, if I were hiring a contractor or employee for that responsibility I would want to do additional testing to make sure they can actually read erection plan sets, shop drawings, know about bolting, and many other issues. Even if they, as I, have several other certifications besides their CWI. Those items are not actually part of the Certification Testing nor CWI requirements under QC1 or B5.1. But, it would be part of doing dimensional examination.
So, I would say they can be qualified, and really should be, but not necessarily certified; not with just a CWI or SCWI anyway. The area you mention, Fabricated Spools, that may be a reach for the average CWI. Not as much for an SCWI but still, how many people know how to read those plans and do dimensionals?
Bottom line, it comes down to the job and the individual inspector, not the certification.
Brent