There are many bayonet car bulb base variants, see
here. Single filament with the common 15mm base are BA15s or 382 and dual filament (stop/tail) bulbs BAY15d or 380 on most Classic Mogs. Obviously the wattage has to be correct for purpose as well in the case of filament bulbs.
An alternate to orange filament indicator bulbs are
no hyperflash amber LED's which won't affect the flash rate.
ETA: note that 581 type although single filament have radially offfset pins so won't fit. You need 382 type as above.
