I have to say it. I have seen many cues that Rambow autographed personally with the name, "Rambow" on them. Rambow made at least 5 or 6 cues for me. They didnt look anything like the fancy calligraphy that you are ascribing to him. His real signature was pretty plain. The cues that Charley Kimmel autographed for him were easy to differentiate.
I would personally tend to think that Charley did that fancy work at the museum as well.
Beard
I am presenting the information as it was presented to me. Obviously I wasn't there to watch him sign it, so I don't claim anything with absolute certainty. However, from a personal and logical perspective, Albert lived with Herman for 25 years. (so they were close) With that in mind, if I were making a cue for my own grandson, I wouldn't have somebody else sign it. But thats just me.