If your about 40, then your first bike probably had DC890 or DC1020's, and then the MX1000 and 900 came out, and they looked totally different - much more "industrial" than the earlier DC's which looked just like the brakes firred to your brothers racer.
I was into BMX from about dec 80 until 84-85 o levels, and from then college/uni where the bmx just sat unused, as no longer really fot for purpose - doing several miles to and from college.
I think by the time I left the bmx scene, dc901 and 880 weren't even out or at least if they were, were not widely available, most bikes were still comming with the earlier brake sets.
For example, even my DB F1 came with 890s, lLearys came with 890s, my Silverstreak too, all bikes from 80-84.
Its when bikes started coming out in ghastly neon colours, and manufactruers stopped with gussets, that my definition of proper old school finishes.
Of course this is all imho, and frankly probably wrong, but with 4 bikes in various stages of being built, I am limited by period to the brakes I can use, and the cheap easilly available 901s are too modern for me.