I called Retrax yesterday and they said the "silver rails" note was for 2018 trucks and older. Retrax doesn't mention this on their ordering page, it just says, "standard rails w/out stake pockets". She said it didn't matter what colored rails I have now, it will fit my truck.
retrax.com
Then, I called RealTruck, whom I ordered it from and he said the same thing. Their page does mention the silver rails.
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realtruck.com
However, I called Retrax again today and talked to another person and she is going to send me some info so I can tell which rail works with my truck and Retrax setup and which does not. She said if the black rails don't work, I can order new rails from Mopar and she's sending me the part number.
Of course, I guess I won't know until installation, but my fingers are crossed. My part number was RTX-80244.
I'm hoping to have my dealer do the installation next week, so I'll have to figure it out, if we need to order the new rails.