HIGGINSFOREVER,
In answer to your question, I study and research original-paint bikes and their serial numbers whenever possible as that is the only truly reliable way to glean valuable information. Original serial number lists, such as the Western Auto book (ABCservices) validate that research.
Dave's site and this site rely on information from collectors like you and I, so the site owners cannot be held responsible for any misinformation that slips through and gets posted on their sites.
"New" information comes to light all the time and sometimes what we thought we knew 10 years ago is proven incorrect by diligent research and information that was always there, but we were blind to it. Quite often it's necessary to read between the lines and do your own research.
Check the catalog pic that Chris posted above for the '58 color and check the "12 Bikes of Christmas" thread (post #124) for an original Red/chrome '55-6 model. You are correct, there were no girls X-53s after '55, as I mentioned in a previous post.
I'll wager that the serial number/letters on Christopher's bike read: MOTX..
Sorry for the rant.