burder is correct - there is no way of knowing for certain. Chrysler did not track combinations of options, only the installation rates of each individual option. They did track the engine/trans combination tho. But, you can usually come up with a reasonable guesstimate for your vehicle based on a few of the main options.

First, there were 23,088 Challengers (Coupes and Hardtops) built in 1971 - but, some of those went to Canada and International markets. If yours is a Base Hardtop (JH23) and was built to USA specifications - a "U" on the second to last row on your fender tag - then your car is one of 17,914 that were shipped to USA dealers. If you have an R/T (JS23), then 3,907 were shipped off to USA dealers.

Now we can address the engine/trans combo.

Of the 17,914 Base Challenger Hardtops shipped, 2.0% came with the 340 & Automatic trans, 1.4% came with the 340 & 4-speed, and 0.2% came with the 340 & 3-speed trans. So that is approximately 358 made with 340/Auto, 251 made with the 340/4spd, and 36 made with the 340/3spd.

Regarding the 3,907 R/Ts, 18.7% came with the 340/Auto, 8.0% came with the 340/4spd, and 0.9% had the 340/3spd. That's around 731, 313, and 35 respectively.

Since you stated that there were 1078 340 cars - that matches the 340 R/T production. I am guessing that yours is an Auto, so you are looking at 731 cars built with that configuration.

Now we know that GY3 Citron Yella was a little more popular on R/Ts than on the rest of the Challenger line (Installation rate of 6.7%). But we don't know if it was more popular on 340 cars, or 383 cars, or Hemi cars - etc. But it would be fairly safe to say that the installation rate of GY3 on the 340 cars was not any more than 10-12%. So if we multiply 731 (340/Auto R/Ts) times a safe 12% (Citron Yella guesstimate) - we get no more than 88 cars of that combo.

So you are easily looking at no more than 100 R/Ts that came equipped with the 340/Auto combo that were painted Citron Yella.