La Pavoni made several flanges throughout the years. Here are some explanations:
1. https://lpowners.org/timelines (scroll down to HEATING ELEMENT FLANGE) = my site
2. http://www.francescoceccarelli.eu/La_...
Sites talk about Pre-1982 fine-thread flanges (M80x1.25) and coarse-thread flanges (M80x1.50). It's best to buy a metric thread gauge and check out for yourself before replacing it. [https://www.amazon.com/dp/B07J9V9JTK?...] I learned the hard way.
OEM fine-thread flanges are no longer made by La Pavoni. Luckily, you can buy replicas from Tudor [https://coffee-sensor.com/product/la-...] and from Stefano [https://espressocare.com/products/la-...]. La Pavoni still makes the coarse-thread flange, which is currently used.
Also, La Pavoni used available parts when they transitioned to new parts, so you can't go just by the year of manufacturing of your machine.