Historically, every gold-related item in Minecraft (aside from ores and raw gold) has had a chance to generate inside a ruined portal chest. This is not the case for golden spears and golden nautilus armor.
To reproduce (in-game)
/give @s chest[minecraft:container_loot={loot_table:"minecraft:chests/ruined_portal"}]Place and open as many chests as you like until you are convinced there are no golden spears and golden nautilus armor in ruined portal chests
Can confirm, this is probably an oversight. Rewrote report and will make another report for golden nautilus armor.