The MMX series were 4 ply shells with Reinforcement rings. If the drums have re-rings they'll be an MMX series, but I have my doubts based on those pictures. If they do not have the re-rings they will be 6 ply shells which is what Pearl still uses on their Master series kits today.
Those are poor pictures they provided to you. Some of the drums look like they had the long high tension lugs. However, The MLX, BLX and Custom Z / CZX lines all used similar looking 1 piece high tension long lugs. The MLX, BLX and Custom Z lines were all pro level kits in their day.
Edit:
I see that the bass has 10 lugs per side, so that tells me it is NOT an export. I'm guessing MLX (maple) or BLX (birch).
If you don't mind me asking, how much did you pay?