Nu,
I preface all my remarks with “In my opinion………”.
1. Based on a highly generalized and subjective opinion, most anyone can grade a cob coin with a reasonable about of online research since cob grading categories are so broad; nothing like the 1-70 grading system for US coinage.
2. As to certification, that is a twofold subject: (1) Certification of Authenticity (Is it real?) and (2) certificate of provenance (From what vessel, for example.) Both forms of certification (sometimes combined) are ‘backed’ by only the reputation of the source providing the cert.
‘Caveat emptor.’
3. As to added value, marketing has, perhaps, the greatest influence on the added value if two similar coins are certified by the same source as genuine and of the same grade (quality). ‘Added value’ is attained by instilling a perception of added value based on the marketing skills of the seller. The historical importance (or 'hype') of a particular vessel over another, on which coins are found, is a substantive current-day 'justificaion' for ‘added value’.
4. What would be your motive to have the cobs graded/certified? Is you intent to resell them? My opinion might differ based on your intent.
5. If your intent is to sell them, then (honestly) 'hype' them for all it’s worth. If your intent is to hold them, then enjoy them for their eye appeal, historical significance, rarity and your ‘bragging rights’.
Don……..
