It would only have been found for sale as "ECG" until New Tone Electronics bought them and quit using that prefix altogether.
Got a pic somewhere of a pegboard plastered with New Tone's original "baggie" semiconductors. Used the prefix "TCG". They were cheaper than Sylvania's "ECG" brand. In part because they did not, at first, have the expense of printing a cross-reference book, let alone the expense of compiling the data that goes into it.
New Tone got sued by Sylvania's "Electronics Component Group". "TCG" was an obvious ripoff of "ECG" and a violation of trademark law.
New Tone lost. Changed the prefix for their replacement-parts line to "NTE", as in New Tone Electronics.
Decades pass, and they purchase "ECG" from Phillips NV who had bought and absorbed Sylvania decades before.
Full circle.
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