Yes, I suppose 1 and 4 would be all you’d need to make it look good enough to fool someone initially. The purpose of the log book is to make sure there’s an independent way to verify what I did or did not do. Partly, it’s a way to verify that I followed all of the necessary steps, such as checking identification.
If I lost the log book or stamp, my state requires me to report that it went missing as soon as I become aware of it. So it would not necessarily invalidate everything I’ve done; courts can look at how close an alleged forgery is to the date I reported it missing.
Also, when the stamp expires or if I ever dispose of it, I’m required to deface it so that it can’t be found in the trash and used.