Put this script in the root prim of an object and touch whichever face of whichever prim you want the texture UUID of. It will be chatted to you. If you do not have permission to get the UUID you will not get it! A long held touch will delete the script.

 

// V2 //
 
integer tc;
 
key owner;
 
default
{
    state_entry()
    {
        owner = llGetOwner();
    }
    touch_end(integer nd)
    {
        while(nd)
        {
            if(llDetectedKey(--nd) == owner)
            {
                tc = 0;
                llOwnerSay(llList2String(llGetLinkPrimitiveParams(llDetectedLinkNumber(nd), [PRIM_TEXTURE, llDetectedTouchFace(nd)]), 0));
            }
        }
    }
    touch(integer nd)
    {
        while(nd)
        {
            if(llDetectedKey(--nd) == owner)
            {
                if((++tc) == 20)
                llRemoveInventory(llGetScriptName());
            }
        }
    }
}