This is directly from Glen E. Fryxell’s “From Ingot to Target: A Cast Bullet Guide for Handgunners”,
Chapter One
Introduction: A Brief History of Bullet Casting
A direct quote from Fryxell’s poublication:
“ …...Lachmiller of Glendale, California entered the loading tool business in 1952, and offered a complete line of reloading tools, dies, sizers, presses, etc. In 1969 Lachmiller introduced a line of well-made 2 and 3-cavity bullet moulds. Lachmiller continued to make bullet moulds into the 1970s, but then sold off their product line to RCBS in the later part of that decade.”
So from that source, Lachmiller was acquired by RCBS in the late 1970's
From other sources it appears the Lachmiller Lube Sizer became the original RCBS Lube-A-Matic which was then later replaced by the Lube-A-Matic 2 or LAM II.