A photo may help, has it possibly been proofed? Check the left side of the Barrel, on the chamber...
Member 12131 has reported a X6E Supermatch, U 938 XXX with a Proof of "BH", which is from 2017, and a X5E Open U 941 XXX also with a "BH" proof, so your pistol likely "BH" proofed too, so 2017 date of birth. If you had the cardboard sleeve rhe case was shipped in, it may actually have a label with the date... similar to this.
Member 12131 has reported a X6E Supermatch, U 938 XXX with a Proof of "BH", which is from 2017, and a X5E Open U 941 XXX also with a "BH" proof, so your pistol likely "BH" proofed too, so 2017 date of birth. If you had the cardboard sleeve rhe case was shipped in, it may actually have a label with the date... similar to this.