there might be a fitting somewhere that allows you to run without them, but Ive never seen it. maybe the ones suggesting this are thinking of v-belt timing cover or d2/p38 covers, and not d1/ 4.0 90
The install angle looks funny, like it would foul the ac heat shield if it weren't chipped. do you have the clamps that tie the 2 lines together? its supposed to be where the 2 hard lines from the radiator are crimped to the soft lines.
Ive got d1s, but the same parts as yours. I installed trailheads on one of mine. OK I guess. all the others get proline or whatever non genuine replacements are out there maybe every 10 years since 98. I dont want to jinx myself, but no problems with them so far