I've seen a few 1799 George III British Pennies for sale at coin shops and flea markets, but I read online that none were made from 1798-1805. Are they contemporary counterfeits?
Not sure about the production of counterfeits but it's interesting that pennies were not produced from 1798-1805. The war between Britain and France was raging during that time and Britain was on the verge of being invaded by the forces of Napoleon. The British must have reserved the copper exclusively for warship production for the Royal Navy.
are you sure it wasn't the Half Penny you saw. this is it. it doesn't say 1/2D on the coin so maybe they were confused on listing it. just my guess. They made the half pennies 1770-1775, then a break until 1799, then a break until 1806 and 1807. this was a major complain with people and why a lot of trade tokens surfaced because the lack of 1/2D and 1D coins. They did make 1D and 2D's in 1797. this is an example. not sure which one you saw.