Topps never released a Part 4, because at the time, the Bubba the Love Sponge/Gawker (can't believe I typed that) tape was surfacing where Hogan was caught on film in private saying some racial things, WWE severed ties as we know and the set wasn't released. Topps in its place released the nWo Tribute in 2015 WWE Heritage, found here:
https://www.tradingcarddb.com/Gallery.cfm/sid/120481/2015-Topps-WWE-Heritage---nWo-Tribute
It even continues the numbering, where the Hogan set left off.
CJF, from the middle of nowhere. Hiya buddies!