I bet a previous owner must have swapped in the 130 mph speedo at some point. Only way that could have happened. Good news is you don't have to hunt for that part.
Sorry, but I have to ask. If you have the analog dash, then I'm guessing you have the harness with all the appropriate connectors. Why not just swap the harness and make it easy on yourself? I know you said you didn't want to discuss that, but curiosity has got the better of me now.