I have some 34a’s from what I thought was a reputable source and they have measured anywhere from .4 to .7 with a couple shorted out they look good though and probably 1/3rd of them are in the .35 to .38 range. I wonder if it’s just older stuff and variance who knows. I have found the ones that test good to be usable as clipping diodes for. A slightly different flavor than 4148’s. Other trusted source mine always hover right around .32-.35 ish it seems I pretty much will only buy them from stompbox parts anymore.
My klon build I did the breadboard thing soldered a couple wires in ran them to a bread board, auditioned diodes. If I remember correctly I ended up with some 34’as that measured in the .32-.35 range.