-
Those track rims:
I'm fairly sure you could use them with brakes, but they may be made of lighter material than the standard version and so would be more fragile.
A clubmate once used a pair of Super Champion 'Medaille d'Or' rims for road racing. These were intended for track use, but could be used for TT's as long as the rider kept a very good look out for anything resembling a pot hole; they seemed to be made of material not all that much heavier than kitchen foil.
It's not possible to watch out for imperfections in the road surface when you're in a bunch,and my chum soon found himself sitting on the road watching the peloton disappear into the distance - he had hit a modest bump which caused both wheels to collapse.
Thanks for helping identify them, I may not have noticed unless I had stored them next to the other rims or fitted them to use with brakes.