It is unlikely that this is the case, but (in a past life) we worked on expanding the cinema color gamut from REC 709 to a new standard called REC 2020 (BT2020).
Since these LED lights can be used for multiple purposes, and REC 2020 hasn't really taken off, perhaps the factory designed the LEDs to meet REC 2020 specifications, and somebody bought them for another application already stamped "2020" at the factory, maybe part of the plastic mold for the body.
Of course, just as with Made in China "organic" products, do not believe that they meet the actual standards as the US and EU defines it. These could be ones that didn't meet the tests for REC 2020, but who would care if used in another application ...
I think that’s something else. For surface mount LED’s, “2020” would just be the length and width x10 (2.0 mm x 2.0 mm actual). Then there would be different prefixes or suffixes to delineate variations or series (efficiency, voltage [as with 2 or 3 “chips within a chip”), etc.
For example: https://cree-led.com/products/j3030/jseries-3030