A bit off-topic but not too much One can notice sentence "The Limone Costa d’Amalfi and the Limone di Sorrento have both been honored with the IGP status (Indicazione Geografica Protetta) status..."
Let me add more info (possibly interesting to a real citrus grower - producer) about IGP i.e. PGI (Protected Geographic Indication):

PGI Approval: http://www.limonedisorrentoigp.it/english/limone.swf

"Study Tour: Geographical Indications - The Citrus Industry in the Amalfi Coast and Puglia Regions, Italy"
http://www.eastagri.org/meetings/docs/meeting66/Study%20Tour-summary.pdf
A few topics from above:
Amalfi Coast Lemons, Visit of "Limon Terrazza"
Visit to the Arancia del Gargano IGP and Lemon Femminello del Gargano IGP
Visit to Clementine del Golfo di Taranto IGP

Okay, Laaz, here are some photos of my mystery lemon tree (that's Deadline squirted on the bottom of the trunk and base of the tree due the March of the Snails at my house):



Interesting almost serrated leaves:


Definitely a lemon and not a citron, as flowers are purplish as is new growth and tiny new lemon fruits:


And an example of a lemon. This is one of the smaller ones:


They are seedless or nearly so, and the skin is a little bit thicker than a Eureka.

Hmmm. That does look like a citron as well. Both of my cittons produce purple flushes, just like my lemons.

Somewhere I read that acid citrons have purplish new growth and acidless citrons have green new growth.

As far as I know, the basic thing, which distinguish pure citrus medica aka citron and citrus limon aka lemon and hybrids of citrus medica x citrus limon is, that pure citrus medica has no separation line between leaf and leaf stalk.