70 Challenger Correct Headlight Bulb Education Needed

[schlett7nu1]

All
I'm looking to address some minor changes made over the years to my 70 Challenger R/T survivor car.  It's currently got four Halogen bulbs installed.  I suspect these bulbs are better.  I don't drive the car at night.  I'd like to hunt down some correct GE 4000/4001 bulbs.  I see a lot of NOS GE high/low bulbs available.  However, I've seen some advertised as correct early version bulbs.  What are the correct bulbs for this application and what distinguishes early from later bulbs?  I'd like to buy a set of correct GE bulbs.
thanks

[Cuda Cody]

Is there a date code on the lights?

[6bblgt]

the lens design used in '70 & earlier is referred to as "WIDE FLUTE"
in addition to GE some Westinghouse have been found to be OE, sometimes in combination with GE on one car
there are date codes, but Windex will remove them

[anlauto]

...may I add...to find a complete set of matched correct bulbs will be expensive.

[70 Challenger Lover]

In the 60s era world of GM, I see people referring to T3 lamps. They look to be interchangeable. Are they only GM or is it an earlier lamp design?

[6bblgt]

T-3 headlights are GM exclusive & reproductions are available

Tung-Sol was another brand - maybe used by FoMoCo 

[js27]

These are what I believe to be the original bulbs off my 70 Challenger. One Westinghouse and 1 GE both with 9--69 date coded for my 11-69 built car.
JS27

[schlett7nu1]

Thanks for all the responses.  The image highlighting the flute differences is awesome and extremely helpful.