I'm looking for the coords of my item, but it doesn't say under the items tab. The location just says:

Palace Mordare\'s Mansion

Any help is appreciated. Thanks!

It means that the item is docked inside that facility. Since you don't have access it won't show the location (or maybe its only if you own the entity its docked inside). Anyway, you will have to use IC methods (such as the Traders Lounge) to locate the owner/location and get access.