There was recently a discussion in the German forum about whether Piaggio has made a technical change here, at least for later model years. The following was noticed:
Piaggio seems to have updated the part number for the oil scraper ring and one of the piston rings:
Upper piston ring: 1A011379
Middle piston ring: 1A013666 (current) replaces 1A011380 (old)
Oil scraper ring: 1A013667 (current) replaces 1A011381 (old)
Note: old numbers in a row xxx79/80/81 and both new SKUs xxx66/67
First of all: A new part number may indicate a changed component (but this is not necessarily the reason for a new part number).
So far, it has not been possible to determine when the new part numbers were introduced. From this it would be possible to deduce when Piaggio could have made a change in series production.
There is almost no source that mentions the "old" article numbers, only ScooterCenter mentions old and current article numbers:
https://www.scooter-center.com/en/piston-ring-lower-piaggio-oe-74.5mm-vespa-gts-hpe-300-zapma3600-zapmd310-vespa-gts-super-hpe-300-zapma360-zapmd3100-vespa-gtv-hpe-300-zapma3602-zapma362-zapmd3102-piaggio-mp3-hpe-300-zapta2100-zaptd2100-gp1a013666
https://www.scooter-center.com/en/oil-scraper-ring-piaggio-oe-74.5mm-vespa-gts-hpe-300-zapma3600-zapmd310-vespa-gts-super-hpe-300-zapma360-zapmd3100-vespa-gtv-hpe-300-zapma3602-zapma362-zapmd3102-piaggio-mp3-hpe-300-zapta2100-zaptd2100-gp1a013667
It would therefore be interesting to compare these parts from an earlier HPE engine with the current part numbers to see if there is a recognizable visual/technical difference.