Sort of.
You need to read it as 'Added' weight. Ships all have a base weight and nobody has calculated this yet. Indeed, I'm not sure the information is available to enable us to calculate it.
So, with just the loaned C2 pulse laser, a docking computer, and a full tank of fuel, your ship is 4t heavier than standard.
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Fuel has weight too, and reportedly, with a partially empty tank (and no weapons or kit), your ship can be lighter than standard and you can actually eek out longer jumps. (I haven't tested this yet, but wether it is in the beta or not, I am pretty certain it will be effect in the full game)
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Of course, I could get all pedantic and point out that weight is a function of gravity, and that in a zero gravity environment, everything has zero weight.
Mass is measured in Newtons.
Weight (measured in Kilogrammes, [1 Tonne is 1000kg]) = Mass * Force of Gravity.
Force of Gravity on Earth is normally given the value 9.8 (or 9.78, or 10, dependent on how accurate you want to be), and it's an acceleration, so is measured in metres per second per second.
Really not sure why FDEV have decided to give us the weight of our kit, as that will vary dependent on which space station we are at (Different station types create different ammounts of gravity), or wether we are in open space (Zero Gravity).
