oil cooler lines

[spork2367]

Kind of an NCRS question, but putting it here for visibility.

So someone had asked me about some oil lines I had and we were trying to discern what the original appearance is. I have a NOS set, pictured, with zinc dichromate ends on the oil filter housing side. The oil cooler side is bare aluminum.

I have a low mileage 1991 parts car. It has 20k original miles and hasn't been street driven in probable 20ish years. I have no reason to believe that the lines aren't original as the car was off the road before reproduction oil lines existed. The oil filter housing ends are black and the cooler ends are bare aluminum.

The reproduction lines you see always show that they are painted black on both ends.

My 91 lines also don't appear to have writing on them while the NOS set I have has GM part numbers printed on them.

Last pic is the repops.

What is correct and for what year?