After digging around some more I found Chris Haynes pics of case numbers. The stamps are done in virgin casting anything other than that is a red flag.
Thanks Speeding Big Twin for pointing me in the right direction. The casting around the case number is smooth and I have drawn my conclusions. I'm a newbe to vintage Harleys and I have much to learn.

 

You're welcome. Re the frame, a clear close-up of its VIN may have helped resolve the year and model. There may also be forging ID higher up on one side or the other of the steering head that would help determine model year. But if the frame has been powdercoated then all these things may be harder to read than if it was painted.

Regarding the pictures of case numbers you found, I advise extreme caution for anyone viewing those examples. Some numbers there which are not consistent with factory stamping are not described as such. It’s a long story but I can send you some details via PM in the next day or two if you wish.

I’ll comment further about the 73 engine number in your ‘Bogus numbers or not’ thread.
Eric