SME with the Companies inherent engineering prowess from the day, could identify and produce a mimic in days once a few designs with dimensions were on paper.
As Pattern Makers, Milling a Wand from any material to create a Part to be shown on a Prototype will have been a job for a apprentice.
@best-groove No need for me to supply anything, the Dates are the History and these are recorded very well.
A Search should even reveal that the RB 300 has a Gross of a estimated 400 000 sales, of which a substantial amount of sales were accumulated in 1983,84,85 (Shedloads)
As for Magazines, when SME were finally getting reviews of the launched V Tonearm in the Mid-Nineties, there is seemingly the usual influence from a Manufacturer, where the only reference to a Competitor Arm (RB300) is where the strengths are made known as improved on the competitor and how these are claimed to be better. No A/B Arm Comparisons allowed in any form of a Description.
The Idler Drive Community did that, and pretty much made it known the RB 300 was as a good a match as a SME V or IV when used with this Motor Drive.
Again interesting how Linn, with their TOTR Tonearm of this era, was a close mimic of a Swiss Brauer Arm.
Was the SME IV and later 309 produced as a cheaper V, to give a more affordable entry, or as a Model to tempt more customers away from Rega's continuing success in creating sales to SME?