Question on small (taillight, interior, etc.) bulbs

[DeS-11]

Hello everyone, it's my first post here. Being new to the 6V side of things, I had a question regarding bulbs. I realize that the headlamps are different between 6V and 12V systems, but what about the taillamp, signal, interior, etc. ones? For example, is a "55" bulb or an "1129" bulb just what it is regardless of application, or are there 6V and 12V versions of them to be aware of? 

 

[LazyK]

Simple answer lamps(bulbs) are voltage specific. A 12volt lamp will have a different number. 

[Doug&Deb]

Most of the bulbs are available. I’ve gotten some from RockAuto.

[DeS-11]

Thank you to you both. That confirms what I had thought, but I was questioning myself due to actually seeing several of these on the rack at the local big-box parts store, when you might figure that there'd be little demand for them.

[LazyK]

Example 

1154 6volt , 1157 12volt

Are both twin filament and will fit in the same socket.