You would first need to consider the following:
Are you just considering a '67 vs. a '73 or between '67 and '73? In '67, the GTJr. was in production and it had a 1.3 liter engive vs. a GTVeloce which had a 1.6 liter engine. Those models not including '68 since they were not imported in the US are known as "Stepnose" Coupes. Beautifully detailed a bit more spartan than the later versions. The Alfa grille is largest in these models, beautifully detailed over the lip of the hood. (See first picture)
'69 1750 GTVeloce: Diplacement of 1.8 liter (although named 1750 in homage to pre-war cars), are known to be the more sought after models for they have the most flexible engines, sportiest interiors including the "wild seats" (only on the '69's) and the four headlights in lieu of the two from earlier cars. Dual booster servo inside engine bay.
The '71 model is similar to the '69 model except that mechanically the car was improved. (See second picture)
The '72 thru '74 models increased displacement to 2 liters. Kept the four headlights and lost the solid Alfa grille and used a more distorted horizontal detailed one. More powerful engine but less flexible, not able to rev as high as the 1750's. The interior is slithly changed, using plastic in lieu of glass on its dash instruments also losing the Miura-like binacles of the 1750's. (See last picture)
In regards to restoration shops, it's too much to cover here. If you want to give me a call, I can help. I had my '71 1750 GTV restored back in '93 and it still looks and runs pretty good. I have also restored a '74 Spider and I'm in the process of restoring a '67 Giulia Super. Mike Besic (630-469-5626) did the mechanical work on my '71 GTV and it continues to run outstanding. Giovanni D'Avola of Autosprint ( 773-685-0930) worked on the mechanical work on my '67 Super and I'm also very pleased. The bodywork on my cars and the cars of many Alfisti was done by Carlo Vaniglia of MOdena Autobody (708-423-2239). There are also Al Promisco and Erik Goldman, both do excellent mechanical work.
I would suggest you join our local CAROC club, it's a great way to exchange this type of info. I won't tell you any more until you join.
If you have further questions, send me a PM.