Thanks Vio
So if I read your Post correctly...
the Cream bridge only was available as a single item purchase (not in a set)
The Brown bridge only came as part of the C-62 Kouka Set
The White bridge was sold as an individual item and 2 of them came in the Hikari Goko Set
I have a theory about why the white bridge is a bit different with no tabs and plates on the connection points. Because the white ones came in that set as a pair and shown connected, they couldn't have the tabs because they can't be connected together. I also assume that the white bridge came last and the mold from the brown and cream had to be adjusted so they could be put together.
So if I read your Post correctly...
the Cream bridge only was available as a single item purchase (not in a set)
The Brown bridge only came as part of the C-62 Kouka Set
The White bridge was sold as an individual item and 2 of them came in the Hikari Goko Set
I have a theory about why the white bridge is a bit different with no tabs and plates on the connection points. Because the white ones came in that set as a pair and shown connected, they couldn't have the tabs because they can't be connected together. I also assume that the white bridge came last and the mold from the brown and cream had to be adjusted so they could be put together.