I typically sign and date my work as well, either the bottom of the base, or somewhere within the model itself. In the case of this clipper, I intend to add another letter to the inside of the hull indicating the restoration/preservation techniques I used on the hull, and detail the project with images. I just hope that 200 years from now someone will be able to read a CD-Rom!!!
The original letter was hand-written with a quilled pen. In fact, I sent it out to have it encapsulated (at the request of the owner) since it's disintegrating. Not exactly the ideal method of preservation, but the provenance of the model is more important than the actual document.
About 20 years ago, I was working on a house back in NY, and I was cutting an opening in a wall between the kitchen and dining room, with a nice oak mantle and arching the top, like you'd find in a nice Italian or French home. Once I had the hole cut, I took a section of the drywall and wrote a long, elaborate story about what was happening in the world, and how much I despised the obnoxious homeowner I was working for at the time. I remember listing who won the Superbowl, World Series, etc...and I stuck it in the wall between the studs.
Someday, when that place is remodeled or torn down, I hope someone finds that old board and gets in touch with me. I predicted that by the time someone did find it, it'd be easy to locate someone using computers (this was pre-internet).
Jeff