Ring Set Tops vs. Bottoms

[JDusza]

Got a ring set for a 50 Merc, 3 cylinder. 2 rings per piston.
3 rings are black rimmed, 3 are silver rimmed. They mic the same, both are tapered.
Which are top and which are bottom?
Thanks,
J

 

[Grub54891]

have you dissassembled the old ones? that may tell you what goes where.