Since the designator is non-speaking, how can I see what is behind that OPN?

There can be many reasons why a salesname has several ordering codes. To mention just a few examples: Customer specific versions, special test versions, ROM codes, different wafer thicknesses, different temperature ranges, different bonding wires etc. It is simply not possible to cover all of these reasons in a descriptive identifier.

Please refer to this answer if you want to know how to determine differences between designators.