Not sure if it's retro, but fillet brazed gooseneck dirt drop stems are definitely a retro thing.
https://www.ebay.co.uk/itm/26678079...J4CW6J&hash=item3e1d5ff346:g:XGsAAOSwR4JmJqBE
https://www.ebay.co.uk/itm/26678079...J4CW6J&hash=item3e1d5ff346:g:XGsAAOSwR4JmJqBE
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