Hi John, I think when most people see the Radio-Tel ticket that Andy Babiuk printed in 'Beatlesgear' about Paul's bass, it establishes a certain point of reference in the bass's history.
Prior to this being published, most written accounts have Paul 'refusing' to take the 4001-S in NYC because he had all he needed with playing the Hofner Bass, which made readers think that it was more of a 'no thanks' situation....as if the bass was there in NYC, and Paul got to try it out. This has been floating about in print for years, and was considered bona-fide..oh well..it's all in the wording, and this was the picture that was painted along the way.
When you see the image of that particular ticket in Babiuk's book, it does seem to indicate that DA 23 was a left-handed model at that point in time, January '64...and it also has a written notation as a request for a left-handed model. Perhaps other docs exist that would indicate DA23 being a right-handed model build-up prior to the ticket printed in 'Beatlesgear'...that would be neat IMO..
I would welcome your effort in doing the end-all book one day, John. It'd be wonderful to hear more about the company and see some more of your Dad's slide pictures. RIC has a wonderful and colorful history, both literally and figuratively.