Yes you can usually identify the wheels (gears) by size, descending in diameter from the mainspring barrel down to the escape wheel. You can call them anything you wish actually. I use T1 etc. just to help identify them when teaching. A more common terminology used in clockmaking is Great wheel, Center wheel, etc. With watches…first wheel, second wheel, etc. When first starting out it’s often a good idea to take pictures of the disassemby process. Especially when working with more complicated striking and chiming movements.
Hope this helps,