Congratulations on the find. Older Sonus are frequently characterized as warm. I have had three sets of Sonus beginning with Cremona. If fed a neutral signal they will sound very natural and organic. I don’t know what Gallo sound like.
If in fact they have not been used they will take a good hundred hours to break in. Typically they start a bit trebly and the bass is woolly or just a bit lean. As the speakers break in this will change. Of course, as you said you have not gotten them placed perfectly. Of course their sound depends on the signal you feed them.
Over the fifty years I have spent building and upgrading my stereo system I have undergone some major revisions of what i think a great system should sound like and the result has drawn me to Sonus Faber. The natural and musicality of the speakers old and new is really quit amazing.