This figure seems very low unless you're talking about a no-option coupe.
Vehicle weight will depend on a lot of factors such as hatch/notch, options (leather, A/C, and power options add weight), any added components such as stereo equipment or sound deadening, etc.
If you want the weight for your own personal car follow drgn5.0's advise and use a truck stop scale. Make sure you allow for fluid weights if you've got a full tank of gas.
i have a 88 GT 5.0 with a custom fibeglass enclosure with 2 10in subs, mainly stock and my car weighs just over 3250, i figure since the lx it little light from lack of ground effects like the GT, then it would be a little lighter.
My 85 GT (which is like later year LX's) is 3030 lbs. with a 1/3 tank of gas, including jack/spare tire. My car doesn't have any power options and I took out the air conditioning.
watever weight i lose from the lack of ground effects is made up in the fact i have a huge sub box made of 3/4 in solid wood with two 12" audiobahn subs and like a 20lb 1200 watt amp, power everything, not to mention with me in there its another 200lb