theheartben

I once ordered a graphics card from the warehouse thing and someone had returned their old card in the new cards box - I called amazon and they took care of it though so it was just inconvenient. 

The biggest problem is what voltage drives the original bulbs, it could be anywhere from 3volts to 240volts depending on what supplies them and where in the world you are.
 
An LED is very low voltage 0.7V typically so the ones used to replace bulbs will have a transformer or similar to allow it to operate on the voltage you need.
 
You will need to look at your original bulbs and on the metal casing it should give a V value and a W value, V being the volts and W the watts. If they are not metal cased the details should be printed on the glass but this may have burnt off over time. Generally a fitting type means one voltage so if you can identify your bulbs from pictures you stand a chance.
 
most electronic component suppliers like Digikey should be able to help you with direct LED replacements or you can then search on the net for bulb replacement LED's by the supply voltage, so if you search 12v LED bulb replacement you will get a whole string of them but you should find one that is the same fitting as the your original bulb.
 
If you can't find one that's a direct replacement it gets a bit more tricky and that would be a whole other post about ohms law and the art of soldering.