I don't know for sure if you can honestly tell proof positive that your car came with or without the FE7 Option.
There are things you can look at and possibly tell, but then again depending upon previous owners and what they modified or replaced can be misleading..
BUT.. original FE cars came with a rear sway bar. The bar attaches to the top of where the rearend spring bolts fit. The bar also has attachment to the frame rail along the back of the car. Also for the FE suspension the rear spring will have 7 leaf springs and the std. was/is 9 leaf. Also the front stabilizer bar is bigger than the std bar.. These are a few things that come to mind... I'll post more if I think of anything, or I'm sure someone else will chime in to help
81 was the first year they used the Mono Spring, I won't say ALL automatics got it, because there were a few that got through production with the old 9 leaf spring, not many but a few.
On the other hand ALL FE suspensions came out with the 7 leaf spring.
You can still check for the rear sway bar and size of the front stablizer bar. Some folks changed out their rear spring for the Mono Springs for a softer.. err ah smoother ride
Statistics and playing with the numbers
FE7 (Gymkhana) = 7,803 (Production)
ZN1 (Trailer Pkg, includes the FE7 opt.) = 916 (Production)
The ZN package included the FE option,
If you ADD the ZN1 to the Total FE7 would mean 8,719 built
If you Subtract the ZN1 from the FE it would mean 6,887 built (I'm not sure which way this would work)
So if your car has the (Factory) Trailer Package Option, then it would have the FE Option and most likely if you have the trailer option it also would have the FS1 (HD Shocks).. so what are the odds of your 1981 (of 40,606 built for production year 1981) having the FE suspension????
Numbers / Statistics drive me :W :crazy
Good Luck Shelly Check your Door Tags too for tire size and loads ..