Yeah, the gender thing is incorrect, but I think the round vs oblong holds true... though that might vary more based on variety.
The dryness of the stem is also a bit iffy, as that just indicates how long ago it was picked.
But the color of the patch and amount of webbing are definitely key to picking a ripe watermelon.
@tyghebright Tyghe, really? Watermelons do not have a "gender." (the flowers do, but the fruit is always from the female flower.)
https://www.usatoday.com/story/news/factcheck/2022/04/26/fact-check-false-claim-male-and-female-watermelons/7366708001/