Yes, that's perfectly likely. He would have been going along the prom, then up either Summerhill Road or Broadway, or along Peel Road. The ultimate destination either Mylchreests for the weigh-in (mostlikely), or the Grandstand/Pits...for that he would probably havge been wearing leathers.
Riders left their bikes overnight in Mylchreests before races, after scrutineering. More details from Bill S (oops, in Canada on yet another holiday) Elwyn or riders from that era.
I used to love the weighing in nights at the Manx in the 70s. I could get photographs of riders, helmetless, with their bikes, and of mechanics etc. They mean so much more now than action shots.