I think you're probably right.
Looking at the underside two tanks have oval mountings across the tank and the other has the oval in line.
Same on the white tanks.

Seller has been a member on eBay since September of this year. Lack of transparency is shameful.

This pic shows a few differences between the tanks... #1 tank bungs are longer and vertical in orientation, petcock location is slightly different and the shape of the inside seam edge is also different when compared to #2 & #3 which appear to better match each other. Also the inside saddle area of my original paint late ‘68 tank has overspray pearl white paint not the black base layer. No expert like some here.... just my observations.

He just lowered the price by $500.00

I was sweating on this post appearing here for all your expert opinion and sleuth work!!

Thanks a bunch guys, you've saved me $5k ($usd-aud conversion, plus aud tax takes $3k to $5k for me)

They are still nice and rare though

A bargain at $105 per month for 24 months... LOL

After a discussion with Enduronut I found out that the threads on the 68 DT1 changed to ISO threads around mid year. I have a NOS 68 tank with an ISO factory sticker that has the larger bung. Maybe the smaller bung is for earlier models?

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From what I can see, all three tanks appear to be legitimate Yamaha pieces ... two being the earlier style and the third is of the later design.
These are not factory paint jobs . . . and yes, very likely the three tanks Devin posted earlier in this thread.

I believe we've discussed this seller before . . . only under a different eBay name
yamaha-enduros.com/index.php/forums/the-...rry-no-cigar?start=0

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Sounds like you're giving us some expert observations to me!

WOW .... thanks for sharing .... probably worth it’s weight in gold
T1