Hamsterbait´s guess is right: 144 being more than 1, the only way to properly write this in both Ancient and Modern Greek is by using the plural (χιλι?δες = thousands). So, yes, we do say 144 thousands in Greek to refer to the number 144,000.
Take Spanish, too: un millón, dos millones. etc. (only works for millions, not thousands in Spanish).
You would normally rather indicate non-literal use either by repetition („myriads of myriads“ or „thousands of thousands“) or by using „myriads“ or „thousands“ alone, without specifying how many myriads or thousands.