Watch band bottoms

[goldscraphobby]

Hi. Just getting into watch bands and I see a lot of the bands have "GF Tops" & "SS bottoms" marked on them but some don't specify, just have "1/20 10kGF" or "10kGF"
Most seem like SS bottoms, have mfg name stamped in them like others and "appear" to be SS, but some bottom color look slightly different with no stamped mfg name.
What is the likelihood of bottoms being something other than SS?

 

[BGDOCK]

50/50 ?

 

[goldscraphobby]

Hi. Just getting into watch bands and I see a lot of the bands have "GF Tops" & "SS bottoms" marked on them but some don't specify, just have "1/20 10kGF" or "10kGF"
Most seem like SS bottoms, have mfg name stamped in them like others and "appear" to be SS, but some bottom color look slightly different with no stamped mfg name.
What is the likelihood of bottoms being something other than SS?

Here is an example. I pulled the top gold caps off and wondering if these bottoms are not stainless?

 

[Shark]

I have never seen gold filled bottoms on watch bands. I have seen them on a rare occasion from bracelets.