7,62x51 belgian Sec Plastic M67

we had already several discussions about the belgian Security Bullets M63, M64 and M67, as exemple here:

Now I got besides a box of M67, a similar one, but marked M67A1…both contain the known FN-Cases with this semitruncated plastic-bullet. The pics are not to scale, just to see the difference in markings. As the outside appearence of the 2 cartrídges are exactly the same, I want to knew, if someone knews the difference between an M67 and an M67A1 load…
Any ideas?
Thx Peter
here is the pic of the box and a view on one cartridge…