Bayley;
I scrubbed the internet to find out from multiple forums the following information:
Of reported Sailun failures on various forums, the following dates codes were reported: 2320,3520,4020,4020,4120. I found reports of three other failures where no date code was provided. All of these were Vietnam tires.
I went to my local tire shop last week and the Sailuns were date coded 2621 from Vietnam fwiw.
Therefore, I would hope that you are right. Perhaps 2021 tires are GTG, despite the natural fact that 2020 Sailuns have more cumulative miles and therefore more opportunities to fail.
Time will tell.
I went with Carlisle CSL 16 instead. G rated. 81 mph rated. 14 ply rating. Its all a gamble. All tires today are trash, especially trailer tires. Leave it up to the Chicoms to ruin the ONLY reliable G rated trailer tire on the market.