Thanks to you as well. I am not a handwriting expert where you see similarities I see differences. Which I guess is why handwriting experts exist in the first place. But I do stand by my assertion that the linguistic styles are very different. Linguistic styles are usually consistent even in brief examples. There are exceptions of course,mostly deliberate to suit circumstances or the audience. It is also a reflection of personality. So just ask yourself.
With what we know of Roy Moore at this time in his life in that town does that dedication fit what you know? If you read this without any supposition about the author how old do you think the author would be? How familiar with the person he was writing to? Stage of education? How much thought was put into the wording? How much sense does what was written make? Just some things to ponder.
It's possible that Moore was trying be romantic and personal in Nelson's yearbook, and professional and inspirational at Gibson's graduation.
Also, Moore signed the yearbook in 1997 (right out of law school) and sent the graduation card in 1980, so he may have sharpened his approach a bit in the three years.
-PJ