The stem you need is dependent on the movement in your UPO. Chances are good it is a 2824/2836 or clone of it in which case you could use the ETA stem which is common to all. They can be had as per below.
Ofrei part number 401/1029
Cousins part number ETA28012401
Or you could reach out to the community as I am sure someone probably has a spare or two knocking around in their parts box.
In the end a new one is not necessary but like Ubi said it can be handy just in case.
Agreed. I'm no expert on these but I'm pretty sure the hour markers should have black surrounds. Those look chrome, which was a problem with the earlier reps. Also date is not centered very well.
Did a similar climb for charity several years ago, the United Way I believe. Quite a climb!
553.3m (1,815 ft). Tallest freestanding tower in the world from 1975-2007. Some cool info on tallest towers here. Tall Towers
Our thoughts are with you triplehd. I hope all goes well. I'm sure all will be fine, they can do amazing things.
On a side note that's Delta for you. Very frustrating airline, especially of late.
I think Ubi has covered most of the options. If you have an established relationship with one of the dealers they may be able to get you something. Best of luck with your search. At some point you may want to settle with a placeholder just so you can wear it in the mean time. I pooched the second hand of my SOH and found a generic second hand of similar size and colour from Ofrei to use in the mean time. Looks not bad, of course for you it won't have the nice little B on it.
I like the reflective shots of the tower. How did you like going up? Did you venture up to the sky pod or just stay on the observation deck? Love the glass floor. When I was little we used to look for those that would venture out on the floor oh so tentatively then come running up beside them an jump.