When the Columbia/Ebonite deal went down, Ebonite got the Dynothane brand. While they did not get the shoe line, having Dynorooz shoes and Dynothane balls owned and made by different companies was not the best situation. They changed the name to 3G, which is the current brand that is PBA-registered. If you have a pair of Dynos and you want to bowl PBA events, you'll need to contact Eric Thomas, he can help you out. I believe they have a trade-in or discount program for bowlers affected by the registration change.
The USBC does not regulate shoes at all, so Dynorooz, 3G, and ABS are perfectly fine for regular sanctioned competition.
SH