Model id of an object?

I’m trying to dump data from the models in the #317 cache.

I found the item with id 1536 which according to the cache represents a door.
A door with this id can be found at location 3207x3217 on the map.
The description of this door is “An elf-fashioned door”.

However, when I look at any object-id list online, I find this door has id 1537 instead of 1536?
When I use Tom’s Cache Editor or Rune.Tools and search for object id 1536, I see some kind of banner flag?
And I don’t even know what object id 1537 represents.

How comes the object-id’s I get from reading the cache are one lower than all object-id lists I find online?
And why don’t the models themselves have the same id?

–Edit

Well, seems like I’m a retard.
The object id != the model id.
An object can even have multiple model id’s.

Result now:

Thanks to Stuart of R-S to point out my idiocy!