Magazine seating adjustment

I was instructed at about age 12 to depress the catch when sliding the mag home and then release it when the mag was in place. I will admit that I don't do this when shooting (seating a loaded mag), but it is another one of those curteous little tricks that cuts down on wear. I think that the fitting of the mag cut out to the catch was the main reason the mags were provided the whole serial number. My wood bottom and type 1 mags are somewhat particular about which pistol the will fit well in, however it seems to me that the extruded mags will fit into any Luger I try them in.