This is Captain Romero from the Rogue Trader era. He was later shown in the catalogues as Chain Sword and Bolter 070119/29 and is also seen in White Dwarf 99 (March 1988).
He seems to be named after Cesar Romero, who played the Joker in the 1960s Batman TV series.
Beaky helmet on his belt:
I think that’s 1988 on the tab.