DISCLAIMER: Most dates posted are not going to be the first time the talent wore the specific attire. Obviously many attires were worn countless times. I try to match dates with the accessories included or the most memorable event worn.
WWE Mattel Elite Collection Legends Series 32: Dory Funk Jr.
Attire worn throughout his NWA World Heavyweight Champion reign February 11th 1969 to May 24th 1973
I did quite a bit of research and couldn't find a specific ECW TV/PPV match or segment where New Jack wore this exact “New Jack 187” shirt. The photo above was likely taken at an untelevised live event. That said, New Jack did wear similar ECW shirts with this gear during 1999.