Welcome to AlfaBB, Lia!
Fusi's production numbers posted here
may give you some hints (but also has some errors).
I understand 1959 was a transitional year (certainly for Sprints) but I don't know if this also applied to Spiders. People in the "Giulietta & Giulia (1954-65)
" may be able to better guide you with respect to what details are 750 or 101 or transitional.
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]