CoffeeBar wrote: Year 1961 EN (sn 218) (v. 1.0)
Year 1961 EN (sn 1012)(v. 1.1)
Year 1962 EN (sn 2259)(v. 1.2)
Year 1963~1964 EN (sn 4253)(v. 1.3)
Year 1964~1968 EN (sn 7556)(v. 1.4)
Year 1968~1970 EN (A6137 )(v. 1.5)
Year 1973~1974 EN (sn 50116 )(v. 1.7)

This information is all listed here for easy lookup:

http://www.francescoceccarelli.eu/lapavoni_ep_eng.htm

Francesco's done us a great service in identifying many home lever versions.

Couldn't agree with you more. Beside Francesco You also the same, you contributed a lot of time to answer many newbie ( Including myself ) here in HB. One of the very helpful Vintage lever guru ( I appreciated you here dr.gary )

You're welcome! And Dr. Pavlis is a most generous and knowledgeable contributor who brings to this forum the gifts of his years of disciplined study and scientific knowledge.

Off Cause, Dr. Pavlis is very Science Specialist, I did read if not all but most of his comments here( Home-Barista.com )
But i found his science's knowledge is a bit deep for me to understand. :Sorry for I am not in well education( un educated )

Anyway, I off cause very appreciated Dr. Pavlis and Thank you so much