Nice set of quality machine made reeds. Those strips over the valves are strips of cut bellows tape. Often found on quality
made accordions. The strips are used on the valves of reeds that face the bellows. Their purpose is to keep the valves from
being caught in the bellows folds. I can't see by the pic's if the reed tongues have blue edges but my guess of machine made
is from the rivets.
I have never seen reeds with the base of the reed cut down to that trapezium shape. Generally the larger the base the better, so leaving it rectangular is a more sound approach. It looks like in some pictures (first and third) the rivets are clearly machine-hammered and in the others (second and fourth) the rivets have been hammered by hand. Whether these are hand-made or just hand-finished reeds is impossible to say because the sides of the base has been "shaped" (so a blue side would have disappeared).
The "strange" tape is indeed bellows tape as Jim mentioned. When the reed block closest to the bellows folds is too close for comfort such a tape needs to be added to prevent the leathers from getting caught in a fold and being bent out of shape or even ripped off while playing. I have had to repair accordions with the block too close to the bellows, but not having this tape, and the danger of the leathers getting caught is real!
This trapezoidal shape at the base of the reed tongue is what intrigued me about these reeds. I’ve heard about “keystone “ reeds and thought this might be the shape. I don’t think I’ve ever seen one, until now maybe.
I cannot think of a reason why they were cut this way. Seems like a lot more work. Maybe someone knows on here.