the '89 HB didn't have "the holes". So your H.B. is older than your truck. I'd seat that HB and makes sure it fits the crank real tight. It's real soft iron and gets hammered to a larger size hole if it was ever loose.
The H.B. might look simple but it is very important to have a perfect fit and balance. Cheap Dorman ones are available for around $110. I'd get the $180 OME if I had to do it.

dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.