Clearly a few words have different "meaning" than thousands of years ago re spoken/written. English, French, Greek, Latin. Hebrew. Chinese whatever. Today we couldn't understand if all words had different meanings than in the long past. Does that apply to "sign language"?
Since ASL is a language, yes, it does change over time.
New signs are added, and older signs change.
Fast-changing technology sometimes gets ahead of languages but they eventually catch up.
An example of how the formation of older signs can change is the sign HELP. It used to be the dominant hand lifted the non-dominant elbow; now it lifts the A-shape fist.
Also, TELEPHONE used to be two-handed, using two S-hands, one hand at the ear, and one at the mouth. Since the telephone itself has changed shape and function, the iconic sign has also changed.
So? English has changed over time, too. Who calls their refrigerator an ice box now?
"Posts from hell" from Gallaudet Survival Guide in Signing-revised edition uses BOTH signs for the word "deaf". pages 42/43 3rd printing 1993 Gallaudet University Press Washington D C. I guess your observations hasn't surfaced at Gallaudet yet. I know- supposed I can't read!
In the realm of dictionaries and text books, 1993 is still old.
Yes, both signs are still around because the older people who used the older sign are still kicking. It's also good to be aware of older signs. However, that doesn't mean they are both in common use by today's generation.
Anyway, that doesn't address the original question about "deaf" and "Deaf."