Lesotho commemorative

Ok experts.
I have a 1982 10 Maloti KM#42.
Problem...it only weighs 28.8 grams.
Possible it is authentic despite short weight?
Does anyone know of these coins being counterfeited?
Much Thanks!

The original coins were issued by Franklin Mint, if I remember correctly.
I can't check the certificate since I sold mine Lesotho KM #42 as this is a purely speculative issue with no relevance to Lesotho's history, culture or nature.
But if I am correct about the US origin of this coin, I can't believe that Franklin Mint would state in a certificate 31,1 g weight and issue a coin weighting 28,8 g. The deviation is too big. Therefore either your coin is a fake or your scale needs calibration.

Here is a Washington set sold on eBay now with a box and a certificate, should you be willing to ask the seller a question.
http://www.ebay.com/itm/ANTIGUA-BARBUDA-and-LESOTHO-6-Coins-1982-Silver-Proof-Set-George-Washington-/160857973204?pt=LH_DefaultDomain_0&hash=item2573e1e1d4

What is the diameter of the coin and can you show us some images of it ?

Hi,
 Size is 38.5 mm and the scale is accurate at 28.8GR. Will post scan as soon as I get all the coin paraphernalia off my copier!
Thanks