Aftermarket slabbie tank question

[Bobby]

Hello all, hope everyone is keeping well.

can anyone shed any light on this, I brought this a good year or more ago, it’s a tank for my 1100 86 GSXR, was from legend motorcycles, anyhow I was told it was a racing tank and was off custom fighter. It’s definitely not genuine as the top is flat and no vent pipe from the top. Also it’s really light. See the pictures, how it fixes to the frame isn’t usual. Anyone seen this before? I’m guessing the fixing point has been altered or was made this way for a custom. 
see what you think 

[Dezza]

Is it magnetic? If not, congratulations. You probably have an aftermarket alloy slabby tank, which usually costs a fortune If you don't want it, can I have 1st dibs?

Edited April 24, 2020 by Dezza

[banoffee]

1 hour ago, Dezza said:

Is it magnetic? If not, it’s probably full of filler. Sell me it cheap 

[clivegto]

Looks like a Harris slabby tank. 

[icprey]

NICE!

Airbox portion underneath filled in?  I'm waiting on the magnetic test too.  Hoping for you it is an old endurance race tank.  I can see with the carb side covers this build will turn out racy.  Good luck.