trs2006boy,
As mentioned there are two versions of kuid. kuid:user_id:asset_id and kuid2:user_id:asset_id:asset_version. Your user_id is 320191 while mine is 133655. These are assigned when you register your copy of Trainz. If you create a map (for example) in TRS2006 it will have a computer generated kuid similar to the following: kuid2:320191:123456:1. Trainz will (or at least used to) generate assset_id based on a "range". Maps have a specific range, bogeys had their own unique range, rails had their specific range, etc for every different type of item created for Trainz. These rainges are outlined in the custom content creation guide.
Now, having said that, while Trainz will generate items with-in a range, it does not necessarily mean that the asset_id for an asset you download will actually fall into this range. Auran has left us free to use whatever we want to use for the asset_id. You do not have to follow the recommendation. But if you follow the recommendation, it makes it easier for the DLS to track items that have been used in your custom content.
A good example of this is the case of a map I recently downloaded that used extensive custom content from other creators which where not available on the DLS. When you use Trainz Objects to look at the missing dependencies it gives you a list of items and what it thinks the item is, based on the asset_id range. IE trees, terrain textures, etc.
I have seen asset_id numbers that range from a single digit up to 10 digits in length. Auran recommends 6 to 8 and if you read the CCG (content creation guide) you will find a table showing the built-in assets. Some with have kuids with negative numbers -1, -3, etc for the user_id and typically 8 digit asset_id. for example: the Auran supplied f7 interior is <kuid:-1:100168> and the Alco horn sound is <kuid:-1:42003103>.
Further, <kuid:123456:654321> is the same as <kuid2:123456:654321:1> but if you create a second version of this asset you would have to change to <kuid:123456:654322> where as you just increment the version number in kuid2 format as <kuid2:123456:654321:2>
Now, while searching for kuid on the DLS, you do not enter the 2 which follows kuid (as in kuid2). Simply enter the user_id for a listing of all that creators items or the full kuid without kuid or kuid2 as in 123456:654321 which will give the specific asset.
So, in brief, the user_id is assigned to you the day you registered your trainz serial number with planet auran and the asset_id is either computer generated or assigned by you the asset creator.
I hope this give you a better understanding of this concept.
Have a great time with the sim.
Brian