I spoke with a rep at Remington and found out that the dimpled mag tube is now standard on new Wingmasters and has been for the past three years. I'd seen posts saying the opposite recently, so I wanted let everyone know. The rep reiterated that the dimples could be drilled out or pressed out to install an extended mag tube and that the magazine tube itself could not be replaced except at the factory. What surprised me was that he said modifying the dimples did NOT void the warranty, so that's interesting.
I'm kinda iffy on the dimples with the plastic retainer being on the Wingmaster. It makes it more of a hassle to modify it. If it was an Express, I wouldn't have any issues, but I'm hesitant to take a dremel to my Wingmaster, though I guess a new magazine tube could be installed if I wanted to go back to stock for whatever reason. Anyway, just thought someone might be interested in this info.