I'm not sure what you mean -do you mean the bulbs themselves or the little black (usually) bulb holders. Both differ depending on the period of the car, older probably I'd guess up to late 1967 used what are called miniature edison screw bulbs, later ones I think had capless or wedge push-in bulbs, as still found on modern cars. The bulbholders thus changed too, with the change from the screw-in to the newer type push-in bulbs.
With the early edison screw-in ones, 6 identical 12V 2.2W bulbs were used for the warning lights and instrument illumination. With the change to capless bulbs, the warning lights (ignition, oil, mainbeam and indicators) used 1.5 W bulbs and the other two: panel illumination, were 3W. The ignition light is an integral part of the charging circuit if an alternator is fitted, the field coils being energised via the bulb completing the circuit, it is unlikely an LED type replacement could be suitable there if considering those. I've read in the past suggestions that a ballpark 150ohm or so resistor be placed across the ignition warning lamp bulb circuit, to keep the charging circuit running if the ign warning lamp bulb should fail, but this seems a precaution too far.
If none of the two panel illumination lights are working at all, it might be the fault of the 'hidden' switch at the end of the dash, between dash and door, either being too well hidden from you, or its contacts have become dirty; sometimes sliding it back and forward a few times might cure that problem.
I'd suggest you take a bulbholder out to determine the type, if the earlier screw type maybe try ebay, I see both LED types (not suitable for ign warning lamp) and conventional filament types available, if it's the later type capless bulb then most motor factors or stores should have them but beware of using higher wattage types of around 5 or 6w intended for things like external sidelamps, which might run rather hot and will be far too bright.
Usual disclaimers apply, the above is part guesswork and surmise and might be awfully, terribly wrong; you absolutely must disconnect the battery before removing the instruments, both the lighting switch and ignition switch (if located there) have live feeds at all times, and it is easy to short something against the sharp surrounding metal when groping behind the instruments to unscrew the speedo cable.
If you have further questions, or are in any doubt, try again for more sensible replies; if you get a bulbholder out, post up a picture of it if possible, but it should be obvious which type of bulb or even bulbholder is needed.