They had “citrons” since 4000 BC or more, which came in many different shapes, some with no pulp and no acidity, which wouldn’t work for making electricity. en.m.wikipedia.org/wiki/Citron
Lemons were introduced in Europe around 200 AD, and were pretty rare and expensive.
If you went to biblical times and asked for a lemon, they’d likely not know what you meant, then maybe gave you a citron, which could be of the low acidity kind, then beat you up for being a liar.