The older leg ends have the same length in the set and mainly the connecting nut screwed inside the aluminum tube. This tube becomes a point of contact with the leg or strut and does not have a suitable lifespan for frequent assembly - we can see the damaged edges of the leg ends (no black paint) in PScooter63's picture.
According to your picture, your new upgraded leg ends have a connecting nut extending beyond the aluminum tube and thus the area for contact with the leg or the strut is made of steel and promises a long service life.
The difference of 5 mm in the length of the assembled front and rear legs is due to the construction of the stand.
It is probably not normally noticed by the keyboard player. Maybe the Nord Grand tempts you to place the glass on the top surface

(and luckily it goes to the cables and not to the keyboard).
How to solve the 5mm difference?
You didn't use to put a carpet or an adhesive pad under the triple pedal so that it doesn't slide on the floor, it could reach under the rear legs of the stand and lift them up.
Also can be purchased at the fastener's or hardware store - 4 pieces - Plain washers DIN 126 size M12 and use 2 pieces when mounting the strut at the rear leg of the stand.
Note: the DIN 126 standard is the same as ISO 7091, the dimensions of the part are dia D=24 mm, d=13 mm, thickness=2,50 mm.
I wish you a successful and satisfactory solution.
Vojtech