Not necessarily. With the stem ring removed, I.e. unscrewed, and large red oring removed - and top plate still on and screwed in - I’ve accidentally dislodged the large clear oring. And after months of use with the original it was impossible to put it back in with the top plate in place. The oring was so curly and stretchy to the touch it was hard to pinch it back in. I used my TM for a couple of months without it (and it was fine save the slight glass rattle). The replacement sent by Ville works great and went right in (only two tries).
With the top plate off, which I did a few days ago (bottom plate left on and wasn’t moved), you’d need to sit the large clear oring atop the glass cylinder just perfectly and then put the top plate on, which might disturb the seating of the oring atop the glass cylinder. Might. It’s kinda hard to tell once the plate rests down. I think it might be better to fit the oring with a finger or pencil eraser (or similar) around the top of the cylinder in the tiny groove of a space between it and the plate. Just my two cents.
Ironically and begrudgingly I need to check and likely redo my large oring. I’m still not getting much vapor below 6 where I used to until recently.
EDIT: if you remove/unscrew the stem ring, remove the large red oring and metal cylinder, you can BUT DON’T!!! twist the glass cylinder and possibly dislodge the large clear oring. It happened to me, while the top plate was securely fastened. Be careful...