Briggs apparently used only D-nuts while Murray used only clinched nuts for several sheet metal locations on these bodies. The firewall is an easy place to check. The locations on the firewall are where the speedometer cable clip attaches on the passenger inside, and where the clip for the wire loom from the generator attaches on the driver side near the terminal box. Also check for the Briggs "bug" logo on the lower passenger side cowl:
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