Many of us have been hunting these bush/trees for years, if Walmart had true specimens of this online someone would have posted it awhile ago. There are none currently listed on the website to even check and see if its the real thing or. Aside from rare fruit nurseries here and there that sell them for stupidly high prices, no seedlings have made it to the States for commercial sale. I think there have been a few individuals who have bulk ordered seeds and gotten one or two to actually sprout but you rarely hear from them again on the subject since they literally are growing a gold mine.
Never understood why we don't have these prolific trees here like any other fruiting tree. We can find durian and they are nasty as hell with a super limited range. Hell, I can jump on ebay and find rambutan and they don't even grow them outdoors in FL. But something like the M. Rubra that should have no issues pretty much anywhere in FL, isn't available.