hi guys saying hello to everyone!!

Welcome to C3VR!!
The "build sheet" and the "tank sticker" are the same thing.
Is the title to the vehicle not good enough to satisfy the import requirement?

Perhaps they can clarify exactly what they need/want in the way of paperwork. Do they need a title, a bill of sale, or what?

Finding a tank sticker on a '72 might be hard to do, since they rarely survived unless the car was taken care of really well. Not to say you may not have one on the car, but chances are it has already been removed, or it has deteriorated so far it would be useless.

yea i know is crazy not able to do it just with title

ive been under the car and seem to me that the tank is original and never been taken of cause or rust and corrosion hope is all i got thanks

Good luck with it! Hopefully it will still be there, and usable! Just be very careful removing the tank, as the sheets were usually(but not always) glued on over one of the tanks straps, which will tear the sheet if not removed carefully.
My suggestion would be if the sticker IS still there, and readable, take several high quality photos of it on the tank before attempting to remove it. That way you have documentation that it was there.

Well I am assuming you are attempting to bring the car from Mexico rather than to Mexico.

From Mexico to the USA does require some special paperwork. (NTHSA form) This appears to be mostly for safety aspects rather than to show that the item is genuine.

Hopefully the links provide will aide you in bringing the car with you to the states.

Tuxdude...he's trying to get it TO Meheco...best I can tell, since that's where he lives.
I been rong before, tho...

Then from what I read he is SOL. It looks like the Mexican government feel as though they already have enough old cars in their country jusdging by the link I previously provided. Tuxblacray2009-02-17 20:39:59