I have no experience with cera coat, but I do have a question.
If the firearm is not likely to be traded, then why worry about the value?
IMO, cera coat it.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)