Looking at the Honda OEM parts drawing, it is not clear to me that the cut-off main harness connectors are sold separately by Honda. Check this out yourself.
eBay has used wiring harnesses for sale. salvage connectors from them. I expect the 500R and 500F use the same turn signal connector.
When you buy new factory turn signals, or used on eBay, see if their connectors have a molded-in part number. With luck you can buy the mating connector half from a connector supply house.
2014 CB500F: GSXR600 rear shock, Traxxion fork emulators+springs, Kuryakyn Throttle Boss, IDEA Gear Indicator, Slipstreamer S-06 windscreen, SW-Motech handlebar risers, LED tail light, rubber tank side pads.