It does sound like Doctor Clocktor has been in there as they do normally line up nicely. As it’s nearly impossible to remove the crimped ring without some evidence of tampering, have a look there. The speedo is rubber mounted into the cup and with a gentle pull upwards you should be able to see the bottom lip of the crimped ring for evidence.
BUT, as the others have said it’s all about condition of the harder to source stuff.
Ian