Welcome to the world of use what you can find and you get what we have to sell not what you need or want.
I like to make things where the fastener only holds things together, and whenever possible not dependent on shear strength.
not knowing the design of your trolley or the loads it will see I might have tried if it were possible to machine the axles so they extended into the mounting plates even if only say a 16mm dia, step extending into the plate 3 to 4 mm, unless you are planning on welding the flanged end of axle to the plate making it a stub shaft, then I might have still left a locating boss on that end if it were location critical