Fuel tank cap location

[thunderon280]

I just recently bought a 1989 Sailfish 255. I’m wondering which fuel caps correspond to the main tank and which one correspond to the aux. tank.

Any help?
:?:

 

[RAINMAKER]

FWD cap . fwd tank , aft cap aft tank.

 

[icecreamman]

Fuel tank cap

On my 2001 gulfstream the foward cap is for the auxillary tank