December 1974 Nishijin Circuit Racer: Early production game?

 As mentioned in the previous post, I acquired a Nishijin Circuit Racer.

Soon after, a friend mentioned that I could buy replacement stickers for it. But when I compared my machine with the sticker set, mine were slightly different. The car sticker in the "cloud" is different and my the feature artwork doesn't have the fork in the road around the "4" and "G", nor does it have the second "S" at the start. Fortunately, my stickers are still in decent condition.

And contrary to other descriptions of circuit racer that are found online, the left and right yellow trophy holes start the feature, not the center hole. Center hole opens only the bottom centre tulip on mine.

The funny thing is that when the tire feature is open, you can't see the S, 4 and G lights. Should have used a low profile tire instead ;-)

You can see the S, 4 and G lights only if you look from the side.

Circuit racer is known to be a game from early 1975, so the expiry date stickers would indicate some months in 1976 (S51). But my expiry sticker indicates 50-12 (December 1975), meaning it was released some time in December 1974. Does this mean I have an early production game?

Pachinko Palace imported some rare gem!

Here is a very informative article about pachinko machine expiration dates. I used the article as a reference for my tiny bit of research.