Henri, the front stays are held on with hex bolts, cannot remember now if BSC or BSF? rear ones also with bolts, but early G3L had no front stand, so were same as for front stays, later ones with front stand had special bolts with small cotter pin, so front stand could swivel freely, and bolts could not drop out.
Only studs on the forks were for the spindle caps.
If no-one else knows I can take one out and measure,
I would be surprised if the bolts were BSCY into aluminium.
BSA discontinued that practice pre war and used BSW into aluminium for improved strength.
As the G3L was a wartime developement I would have thought BSF or BSW more likely..Ian
Lex, it is the four bolts that hold that big bracket from the front fender into the fork sliders. The fork sliders are still NOS, with cork fillers into the holes and I did not wish to chance misthreading it. Don't know if that is a real word btw.