https://www.usps.org/national/vsc/fo...iles/a7012.pdf
The Cert of compliance is not required. The link above is the coast guard (VSC) Vessel Safety Checklist. Both are under "Recommended and Discussion Items". Under 20' the capacity placard is required by federal law. Under 26' it is required by NMMA for the MANUFACTURER to install the plate to be part of the NMMA... on a 23' boat there is no requirement for you to have a capacity placard. I wouldn't worry about it.